Make TableColumns case insensitive
Reorder C type declarations

Old Cython version has problems with names used in the file before
they are declared.
Fix setter for property .active_sequence

Do not raise an exception if no sequence was active, before using the
setter to activate one.

Also rename the property from .sequence.
Rename Table.get_all to Table.columns.freeze and return TfsTable
Add function libmadx.get_table_list
Always return 'at' relative to element entry
Drastical simplifications in cpymad.madx
Merge branch 'active-sequence' into simplify-madx

Conflicts:
	src/cern/cpymad/madx.py