Backport PR #2994: expanduser on %%file targets

closes #2993
fix cython module so extension for multiarched python

backported from a1daa0286a867cda86e728e177d72a645b72c634
Backport PR #2831: avoid string version comparisons in external.qt

We have learned from pyzmq that one should *always* parse version strings
before comparing them.
Merge pull request #3008 from juliantaylor/cython-suffix

fix cython module so extension for multiarched python