FIX: free self.estimators_
Merge pull request #2430 from glouppe/forest-2414

FIX: free self.estimators_
COSMIT more typos/precisions
DOC add missing Returns description
DOC: Update pyamg site and fix a typo.
Merge pull request #2432 from jwkvam/docs_cluster

DOC: Update pyamg site and fix a typo.
Merge pull request #2370 from ogrisel/doc-cross-validation

MRG: DOC: Simpler cross-validation iterator doc
MAINT deprecate indices=False for cross validation generators
DOC boolean masks in CV generators are deprecated
DOC what's new: fast_dot is internal, so don't mention it
COSMIT rewrite precision_recall_fscore_support

* Rewritten for efficiency and neatness. Note the handling of multilabel-sequences format by binarizing is in response to benchmarks.
* Also fixed some warning handling in tests
FIX warning interaction problem, DOC clarify parameters
FIX ignore corrcoef warning
Use label_binarize instead of LabelBinarizer
Use specialised warning class
TST messages for UndefinedMetricWarning from prf
TST use ignore_warnings helper
TST classification_report example that does not trigger warning
Merge pull request #2278 from jnothman/prf_rewrite3

[MRG] faster, flatter precision_recall_fscore_support
FIX use fixes.bincount for numpy 1.3.0 support