A big update that wraps over 90% of the public C++ API, with enough functionality to let Python users to perform useful modelling.

Key features
- wrapping of cable cell functionality
  - user-defined explicit compartmentalisation not supported
- `single_cell_model` abstraction unique to the Python wrapper that simplifies developing and testing single cell models
- one-dimensional cell builder for Python wrapper that simplfies building cells that 
  - in and of itself limited in scope, but a very useful example of mapping a richer morphology builder onto `sample_tree`s.
- parsing of region and location expressions from strings
  - implements a generic s-expression parser that we can use for other purposes later

akuesters authored 5 years ago and Benjamin Cumming committed 5 years ago

Ensure that errors in Python callbacks that are called from multithreaded C++ code propogate the correct Python error back to the parent Python callback site, and that no callbacks are called from other threads if an error has already ocurred.
- protects each recipe callback with a mutex, stores python exception, catches and throws python exception if occured
- methods calling recipe (in simulation and partition_load_balance) are protected as well by try catch, resets and rethrows python exception (if occured) or else throws C++ exception

fixes #792

akuesters authored 6 years ago and Benjamin Cumming committed 6 years ago

Wrapped the following C++ features in Python: 
- Identifiers (`cell_member`) + according tests
- `event_generator` and schedules (`regular_schedule`, `explicit_schedule`, `poisson_schedule`) + according tests