Py3: fix version comparison in imputation module
DOC fixing some sphinx stuff.
DOC SGDClassifier has multiclass predict_proba
DOC minor copyedit to narratives
FIX don't use old scoring API in randomized search

Removed score_func and loss_func, which were deprecated the moment
they were introduced.
Add supported python versions to the classifiers + fixes
Merge pull request #2280 from larsmans/randomsearch-scoring

[MRG] Randomized search should use new scorer API
Merge pull request #2281 from ogrisel/improvements-to-setup-py

Add supported python versions to the classifiers + fixes
ENH: add failing test exposing bug in RandomizedPCA
FIX: only center if copy == True
ENH: get it right.
FIX: inverse_transform; tests
DOC better doc message
API: get rid of **params in PCA estimators.
DOC: more doc string fixes in pca.py
DOC: more fixes in pca.py doc strings
STY: get rid of unnecessary identifiers