Use one_hot=True when building MNIST
Import if cuda is available, so that test can use it
Build MNIST with one_hot=True in more cases

Conflicts:
	pylearn2/scripts/tutorials/grbm_smd/make_dataset.py
Add comment reminding to revert changes when the actual problem is fixed
Fix another test
Try to enable test on travis
Relax test tolerance for the other gradient as well
Restore previous value of floatX when changing it in tests
Remove commented-out lines now that Travis passes
Merge pull request #501 from lamblin/fix_buildbot

[MRG] Fix various buildbot failures