REF: refactor platform mocks.
FEAT: add new Platform class.
MAINT: add tox target for coverage.
ENH: add release in Platform.__str__.
FEAT: add Platform -> EPDPlatform conversion support.
ENH: add hashing protocol support to Arch and Platform.
DOC: add basic doc for platform.
BUG: fix testing on non-ubuntu platforms...
BUG: fix testing on windows 32 bits.
REF: use constants instead of string for family attribute.
Merge pull request #30 from enthought/new_generic_platform

New generic platform