Added utility to skip tests if running on Travis
DOC adding return type and improving module doc
DOC return types in datasets.lfw
DOC numpydoc convention for Bunch-returning functions

Also cap lines at 80 chars, remove trailing spaces.

As suggested by @jnothman at
https://github.com/scikit-learn/scikit-learn/pull/3316/files#r14269818
Merge branch 'pr/3316'

Fixes #3316.
FIX multilabel deprecation warning in RidgeClassifierCV
MAINT ignore sparsefuncs_fast in diffs
FIX MinMaxScaler behavior on 1D inputs.
MAINT explicit float64 in sparsefuncs_fast
MAINT mailmap update
FIX #3372: unstable input check test for RANSACRegressor
Added FIXME annotation to skipped test
Merge pull request #3353 from kastnerkyle/skip_ompcv_travis

[MRG+1] Skip test for OrthogonalMatchingPursuitCV if running on Travis
Corrected two typos in docstring.
#3356 - Added an exception raising when np.nan is passed into a HashingVectorizer.
#3356 - Added an exception raising when np.nan is passed into a HashingVectorizer.
Merge pull request #3375 from ldirer/hashing_fix3356

Corrected two typos in docstring.
Added a test on hashing vectorizer behavior with np.nan input.
PEP8 line length fix.
Changed solver from 'dense_cholesky' to 'cholesky' to eliminate deprecation warning.