BUG: Add pytables to the testing virtualenv. #103

Change-Id: I6b392fe62f45e2524bd91d901d46ad6ce523e0b0
ENH: TubeTK_USE_PYQTGRAPH OFF by default.

Larger dependencies.

Change-Id: If403c347613427ac578bf9692299eb5aae75a6ef
Merge pull request #104 from thewtex/python-packages

Python packages