Starting PR to push DBN to Pylearn2.

Added RBM subclass of DBM for convenience.
Add docs to DBM.
Added chain initialization to DBM for some future changes to gradient estimation.

Starting PR to push DBN to Pylearn2.

Added RBM subclass of DBM for convenience.
Add docs to DBM.
Added chain initialization to DBM for some future changes to gradient estimation.

fixed line formatting

Made the docs numpydoc compliant.
Modified inference procedure to have a method "is_rbm_compatible" that will raise a NotImplementedError if not appropriate for RBM.
Removed assert for RBM and UpDown inference.

Made the docs numpydoc compliant.
Modified inference procedure to have a method "is_rbm_compatible" that will raise a NotImplementedError if not appropriate for RBM.
Removed assert for RBM and UpDown inference.