Fixed recipe to test all modules

This package is not been tested properly.

For instance, when you do nosetests -sv bob.rppg.base only the tests under bob.rppg.base are tested. However, this package has more submodules (chrom, cvpr14, ssr). Hence, in order to run all test we need to do nosetests -sv bob.rppg.

By doing that you will see that some tests are failing.

This MR allows us to run all the test, but doesn't fix them :-)
Can someone please look at it?

ping @andre.anjos @heusch

thanks