BLD: travis deps (stats,timeseries, pytables on py2.x), clean setup.py, nose tricks
note that this brings up some currently failing cmov tests (@changhiskhan) which
were previously  skipped due to no scikit.timeseries on travis.

I picked the current statsmodels 0.5 git master commit hash as the 
version to be installed, since pypi 0.5.0-beta raises a failing test in WLS

see http://nose.readthedocs.org/en/latest/plugins/testid.html 
for nose-fu tidbit.
