[Python-apps-team] Bug#545809: bump to recommend

[Julian Taylor]

found 545809 0.17.1-1
thanks

I would bump python-dev and gcc to at least Recommends, maybe even Depends.

In my opinion it is pretty unusual to use cython without also compiling
at some point.
Also dynamic compilation via pyxinstall does not work without python-dev.

See also
https://bugs.launchpad.net/ubuntu/+source/cython/+bug/1048999