Fix bug that kept from warning that Cython is required
Use proper int size; fix for #54
Bump to 0.2.2
Remove AVStream.r_frame_rate

It was deprecated in Libav, and can easily not be compiled in. Their reasons are
seemingly valid, so it is tons easier for us to simply remove it from PyAV.

This hopefully fixes #52.
Disable failing asserts due to missing r_frame_rate