MultiValueEnum takes any iterable now.

Stores values in set internally for lookup.
Overlapping values are aliases.
Tests for almost every iterable types.
Improved documentation for MultiValueEnum changes.

Explained generators, internal operations, types expected, dict behavior.
no_overlap decorator

it prevents MultiValuEnum members to have common elements.
Added missing dependency for tests, added Makefile.
Documentation for no_overlap decorator.
Github style readme.
Merge branch 'multivalue-any-iterable'