Added RBM to whats_new.rst
Added skeleton for RBM documentation
FIX mistake in rst
Rename RestrictedBolzmannMachine to BernoulliRBM
FIX: make BernoulliRBM doctest pass
Merge branch 'master' into rbm-docs

Conflicts:
	doc/whats_new.rst
Rename also in whats_new
FIX: BernoulliRBM check random state in fit, not in init
FIX: validation in `BernoulliRBM.transform`
DOC: first attempt at RBM documentation
Link to RBM docs from the unsupervised toctree
FIX: uneven RBM image
DOC: PCD details and references
Merge branch 'rbm-docs' of https://github.com/vene/scikit-learn into vene-rbm-docs