Cpymad

This is the first independent version released for the `HIT cpymad fork`_.
The changes on the public API are so heavy, that this is basically a new
library.

- rename package from ``cern.cpymad`` to ``cpymad``
- remove LHC models from repository
- redesign API to make more use of OOP (no stable API yet!)
- removed some obsolete / unused modules

.. _HIT cpymad fork: https://github.com/hibtc/cpymad

- fix broken caching logic in travis config
- move type constants to ``cpymad.types``
- export a MAD-X dtype to python type mapping from ``cpymad.types``

- update to MAD-X 5.09.00

- add efficient functions to get list of all element namems
- provide element index within the sequence
- add function to check MAD-X expressions
- make ``evaluate()`` slightly safer
- add windows build scripts (``.bat``)

- expose sequence length as ``Sequence.length``

- update to MAD-X 5.09.01
- add wheels for python 3.12