Issue #2455: Make RBM work with sparse input when verbose=True.
Change RBM sparse format from CSC to CSR.
Cosmetic changes.
Add issparse import.
Cosmetic changes.
Expanded docstring of the verbose parameter.
Check that verbose output is sound.
FIX #2372: non-shuffling StratifiedKFold implementation and updated tests
Merge pull request #2463 from ogrisel/stratified-kfold

[MRG] FIX #2372: non-shuffling StratifiedKFold implementation
FIX: skip numpy.dot + multiprocessing test that segfaults under recently updated OSX 10.8
FIX: broken doctest impacted by stratified CV and tree RNG changes combined...
Merge pull request #2457 from untom/rbm_csr_format

[MRG] Switch BernoulliRBM to CSR format
GBRT enhancements:
  Moved verbose output code to VerboseReporter class.
  Cosmit: logical structured code blocks
  Refactored: moved init state to method
  Added partial_fit to GradientBoosting
  Fix: is_classification not available; n_features not n_features_
  Tests
  Add ``partial_fit`` to docs
added EPSILON_FLT and EPSILON_DBL for almost equal impurity and fx value comparisons
fiddled with EPSILON_DBL
added monitor callback w/ early stopping support