* Sort collected spikes in Python API lfirst by time, then gid, then lid.
* Remove redundant old spike handling code from Python lib.

* Update URLs to arbor-sim.org
* update badge links

* Adapt CSS for the HTML5 transition in docutils 0.17
* Fix some reST markup errors
* Add meta-tag to enable indexation control at Google (current indexation appears at least a year old).

Fix mistakes reported by @Helveg in the Python tutorial docs. 

* fix mech_vec
* fix fvm_discretize
* small fixes

* Add Zenodo citation snippet.
* Correct Nora's last name, which is Abi Akar.
* Small css fix for change in docutils, see: https://github.com/readthedocs/sphinx_rtd_theme/issues/1115

Fixes #1297.

* `i_clamp` constructors take new optional phase argument.
* Pulse or box envelope clamps are now provided by the static method `i_clamp::box`, taking onset, duration, and amplitude parameters.
* Bump pybind11 version so we can have keyword-only arguments in the Python API.
* Make frequency and phase keyword-only arguments to Python `iclamp`.
* Change frequency units for clamps from Hz to kHz for consistency with other interfaces.

Fixes #1454.

* update and simplify the `load_swc_neuron` reader to match the simplified and more correct interpretation in NEURON 8
* update the documentation on the interpretation, and add details about how it still differs from the neuromorpho descriptions. 
* update unit tests to reflect new interpretation
* add a unit test that reproduces a complex case from the NEURON test suite.
* remove the `load_swc_allen` C++ and Python calls
* add links to NeuroMorpho site in the documention

Fixes #1445.

Always install Python module inside CMAKE_INSTALL_PREFIX, unless the user explicitly sets the ARB_PYTHON_LIB_PATH CMake variable.

Update documentation on installing and building the Python packing using CMake to have a detailed example of how to install the Python module inside a virtual env.

Fixes #1403

* Correct the installation page.
* Custom css is not supported by theme, so a css snippet improving table formatting was moved to the theme css.
* Non cable-cell concept docs were wrong, improved formatting
* Some typos

Co-authored-by: @clinssen 

* Implements parsers and writers in `arborio` for the s-expression based Arbor Cable-Cell Format defined in #1336.
* Moves `s_expr.hpp` to the public interface.
* Adds python wrappers to support the features in pyarb.  
* Adds unit tests.
* Adds docs.

Fixes #1336
Partially addresses #1233

Co-authored-by: C.A.P. Linssen <charl@turingbirds.com>

Remove `gid` attribute of target of a connection, and local gap-junction site of a gap-junction connection (#1467)

* Change the type of the target of a `connection` from `cell_member_type` to `cell_lid_type`. The target cell's gid is always known in both the recipe and simulation.
* Change the type of the local site of a `gap_junction_connection` from `cell_member_type` to `cell_lid_type`, and make it such that the first argument of the connection is the peer site, and the second the local site. The local cell's gid is always known in both the recipe and simulation.
* Change the type of the target of an `event_generator` from `cell_member_type` to `cell_lid_type`. The target cell's gid is always known in both the recipe and simulation.
* New `cell_spike_events` and `cse_vector` for `simulation::inject_events`.
* Simplify recipe sanity checks and remove associated exception types. 
* Fix unit tests, examples, docs

* Adds a `neuroml_options` namespace with enum for use with `neuroml::morphology(...)` and `neuroml::cell_morphology(...)`.
* Add support for a 'spherical' root segment with option `neuroml_options;:allow_spherical_root`; a zero-length root segment with identical proximal and distal radius will then be converted into an area-equivalent cylinder in the resultant morphology.
* Amend `place_pwlin::all_at` so that locations on a zero-length segment with different radii at the endpoint will give an mpoint for either end.
* Add `allow_spherical_root` boolean optional parameter to Python NeuroML morphology methods.
* Update docs; C++ unit tests.

Fix orientation of ASC somas from along z axis to along the y axis.

As per the rules followed by Arbor's SWC parsers, and prescribed in:
http://neuromorpho.org/SomaFormat.html

Addresses #1445

* Add `nml_` prefix to NeuroML-related classes in arborio.
* Separate `arborio/xmlwrap` from NeuroML exceptions.
* Put xmlwrap functionality in its own namespace.
* Have xmlwrap property access errors returned by util::expected, so that the corresponding NeuroML exceptions are strictly the
responsibility of the NeuroML parsing code.
* Rename NeuroML implementation and support sources and headers.
* Place implementation classes for Neurolucida ASC parsing in an anonymous namespace.

Fixes #1441.

Basic support for reading morphologies from Neurolucida ASCII (.asc) files.

Added to the arborio C++ library, and wrapped similarly to the other arborio features in Python.

Fixes #1429

* Add Python version of brunel.cpp example.
* Enforce consistency in units: both C++ and Python APIs use unit `kHz` for all frequencies.
* Align Python version `poisson_schedule` signature with C++ equivalent.
* Update unit tests to suit API changes.
* Update documentation to suit, along with minor additions related to networks and interconnectivity.
* Add `brunel.py` to `basic.yml` tests

- Use parameter packs for multicore mechanisms.
- Adjust unit tests and modcc.
- CPU and GPU use the same mechanism_ppack_base.
- CPU code uses a split similar to GPU with `mech_XYZ_foo` and `kernel::mech_XYZ_foo.
- Make mechanism_ppack_base header public.
- Tracing macros for modcc code gen.

* Change implementation of current clamp from a builtin mechanism to
  functionality provided by the back-end shared state classes.
* Extend clamp functionality to cover more use cases: it now supports DC
  and AC stimuli governed by a piecewise-linear envelope.
* Update Python iclamp wrapper to suit; add unit test.
* Account for total applied stimulus currents separately, and remove
  their contribution to the reported transmembrane current and
  ionic (i.e. non-capacitive) transmembrane current.
* Add new probe specifically for tracking total current stimulus in a cell.
* Update docs, and add an entry for current clamps to the concepts doc.
* Remove entirely the builtin catalogue.

* Provide defines and variables for version string components: major
version; minor version; patch level version; development suffix.
* Change commit date format to strict ISO.
* Add define/variable for Arbor build configuration.
* Add usage/help info to `git-source-id` script.
* Add define/variable for a full build identification string,
incorporating source info, version, build configuration, feature
options.
* Add documentation for the version and build defines and variables.
* Extend version unit tests to suit.

* Remove parts of the C++ API which leaked into `doc/fileformat/neuroml.rst`
* Add links to the relevant C++ and Python API

* Auto-generate binary Python wheels, triggered by git tags 'v*'.
  * Wheels are generated for Python versions 3.6-3.9, for Linux using the [PyPA manylinux-2014 image](https://github.com/pypa/manylinux) and MacOS using macos-latest (10.15 at time of writing).
  * The Action generates `sdist` for any other platforms.
  * The cibuildwheel action automatically prepares the wheels using [auditwheel](https://cibuildwheel.readthedocs.io/en/stable/options/#repair-wheel-command), which means bundling of external deps (e.g. libxml2 for NeuroML).
  * The output is all that's needed for publication of a new version to (Test)PyPI.
* `setup.py` defaults `neuroml` to on.
* A small change to `CMakeLists.txt` was required to build the wheels: based on this [Pybind hint](https://pybind11.readthedocs.io/en/stable/compiling.html#findpython-mode) `Development.Module`is now required, and not `Development` when CMake searches for Python. I confirm this change is needed to make Arbor build in the manylinux docker images, but I do not understand what the change implies, other than that we now don't link to `libpython`.

* Refactor Documentation layout. 
* Display Spack page.
* Display Extending catalogues page.

Fixes #1353.