* Replace TCLAP with tinyopt, remove TCLAP from `ext/`.
* Replace `sup/tinyopt.hpp` with copy of external tinyopt, update use of `tinyopt` in unit tests and examples to suit.
* Use tinyopt's 'smallopt' interface in `modcc`, `brunel` example.
* Update tinyopt interface in `single` example.
 Fix our attributions and add HBP acknowledgement

Addresses #557 #695 #803