DOC fix formatting of attributes etc. in docstrings
DOC move Attributes section to after Parameters and style likewise
MAINT use assert_warns
MAINT Fix regression random projections work sparse matrices
Merge pull request #3522 from ugurthemaster/patch-1

Update plot_tree_regression.py
FIX #3485: class_weight='auto' on SGDClassifier
FIX wording in whats new in 0.15.1
Merge pull request #3509 from arjoly/fix-rp-sparse

[MRG] MAINT regression: random projection should work with sparse matrix
Merge pull request #3489 from jnothman/attributes-doc

[MRG] DOC fix formatting of Attributes sections in documentation
DOC remove backticks from around attribute name + PEP8
FIX Exact inverse transform for whitened PCA
TST test whitened inverse
ENH components of unit length and whitening done by scaling with sqrt of explained variance
DOC What's new