SIP v4 for Python 2.7 and 3

Runs under Python 2.7 or 3.
Plugins have been updated for this release and will no no longer work with older revs.

SIP v3 for Python 2.7 only

This is the last revision for Python 2.7.
Plugins have been updated to work with SIP V4 and will no longer work with this release.