Bump version number to 0.5.0a.
Bump version number to 0.5.0a.

--HG--
extra : convert_revision : svn%3Aa2f44796-8cc0-49ac-b43f-6a96d556d52d/trunk%40332

denfromufa/comtypes,denfromufa/comtypes,denfromufa/comtypes,denfromufa/comtypes,denfromufa/comtypes