Cpymad

- add ``Parameter.var_type`` that tells apart constant/direct/expression vars
- change the meaning of ``inform`` for globals, ``inform=0`` means now
"predefined variable"
- fix TypeError occuring in ``mad_command`` when composing string arrays

- fix some inconsistencies regarding the mixture of unicode and byte strings
on python2 (NOTE: still expected to be broken!)
- provide copyright notice as unicode

- Strip trailing underscore from ``MadxCommands`` attribute names. This allows
the syntax to be used even for python keywords, e.g. ``m.command.global_()``
- Change the behaviour of ``Madx.globals``:
- when setting string values, set the variable as deferred expression
- when getting deferred variables, return instances of type ``Expression``
- when iterating, only show non-constant globals

- isolate cpymad: remove jpymad backend, remove pymad base
- bootstrap the dependency on numpy
- remove custom MAD-X path discovery during setup. You should use
*--madxdir* if the library is not installed in a system location.
- add function ``libmadx.is_expanded``
- add function ``libmadx.chdir``
- handle MAD-X table columns with integer arrays
- make ``madx.command`` more powerful (allows ``**kwargs`` and attribute
access)
- use inherited pipes for IPC with remote MAD-X processes (allows to
forward stdin/stdout separately)
- close connection to remote process on finalization of ``LibMadxClient``
- remove MAD-X command checks, ``recursive_history`` and filename
completion
- fix name clash
- fix some bugs
- rename convenience constructors to ``cern.cpymad.load_model`` and
``cern.cpymad.start_madx`` due to name clash with module names

- keep user specified argument order (only py>=3.6)
- update official support to ``MAD-X 5.03.05``
- build the windows version with GC

- add csv() method for ResourceProvider
- use C loader from yaml for performance if available
- convert madx.metadata.get_copyright_notice
- add accessors to real sequence + elements for model.Sequence