Roughpy

- Added free functions for performing free-tensor, shuffle, half-shuffle
multiplication between pairs of tensors (of either kind).
- Added free function for applying the adjoint of left free tensor
multiplication to arbitrary tensors.
- Improved exception usage, messages now include filename, lineno, and
function name to help locate c++ exceptions passed through to Python.
- Basis objects in Python are now iterable.
- Added `split_n` and `to_index` methods to Tensor key.

- Overhauled the RPY_CHECK macro so it now gives much better contextual
information.
- Readme updated to reflect PyPI installation with wheels.
- Antipode is now implemented in libalgebra_lite, and exposed to Python for
Free tensors.
- Streams now carry a support interval, outside of which the signature will be
return trivial.
- Build requirements fixed for non x86 platforms.
- Expanded coverage of pytype stub file.

- Added datetime interval support.
- Integrated schema reparametrisation into stream signature methods.
- Fixed bug in names of scalar types, names now display correctly.
- Fixed bfloat16 given wrong scalar type code.
- Added half precision float and bfloat16 to py module
- Added real partition class and Python interface.
- Implemented simplify method on Streams.
- Added polynomial coefficients
- started an examples folder

- Added datetime and timedelta object support to tick data parsing.
- Expanded build system to include more versions of Python.
- Stabilised compilation on all three platforms.
- Fixed numerous bugs in the build system.

- First alpha release.