rel_canonical prelim
DOC : fixes in covariance module
DOC : more fixes in covariance module
cleaned up-ready
nitpick fixes, pep8 and fix math equations
fix: python3.3 warning fix
Merge pull request #6 from jaquesgrobler/cov_doc_fix

nitpick fixes, pep8 and fix math equations
Merge pull request #2203 from agramfort/cov_doc_fix

doc fixes in covariance module
ENH simplify the Scorer API

A Scorer is now a function that returns a score that should be maximized.
FIX bug in scorers that take probabilities

The class implementing this did not actually work and was never tested.
Found this out while rebasing #2103.
removed old_version block test
Merge pull request #2205 from jaquesgrobler/ENH_rel_canonical

Enh rel canonical
ENH added Restricted Boltzmann machines
30% speed-up thanks to in-place binomial

From https://gist.github.com/359323.
ENH 12% RBM speedup with ingenious ordering of operations

+ inplace gradients for components_, 2% speed-up
rename h_samples to h_samples_
added URI for RBM reference
improved docstring for transform
renamed _sigmoid to _logistic_sigmoid
use double backquotes around equations