Fix as_float_array behaviour when copy=True
Add test of the as_float_array behaviour when copy=True
rel_canonical prelim
cleaned up-ready
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
logistic_sigmoid moved to function
transposed components_, no performance penalty
only compute pseudolikelihood if verbose=True
more accurate pseudo-likelihood
use iteration terminology instead of epochs in RBM