MAINT: add `__credits__`
DOC: explicit signature of ids_to_keep, docstring changes
MAINT: better func name
STY
MAINT: better to explicitly convert to bool, even if we ask `func` to return bools
ENH: add more general filter function
MAINT: cleanup of format conversions
ENH: add `general` parameter to _filter
ENH: add `Table.filter_general` method.
MAINT: update .c sources
TST: test for general filter
STY
Remove specific filter method.
Make filter_general the only filter
Remove non general filter from pyx
Remove private non general filter
TST: fix tests for single filter version
MAINT: update .c source code
Merge pull request #355 from Jorge-C/general_filter

General filter