Add sample_weight support to Dummy Regressor
Use np.average instead of np.mean
A short cleanup
recovering deleted variable
Handle_unknown option to OneHotEncoder

OneHotEncoder fails with a error that is not helpful if a missing
categorical feature is present during transformation.
Add handle_unknown with an "error" and an "ignore" option.
DOC: Remove extra # from url in fit.

The extra # messes with the rst parser which produces an invalid URL where the ".html" suffix is missing.
Merge pull request #3797 from Titan-C/clean

A short cleanup
Merge pull request #3801 from cmd-ntrf/typo_vbgmm

DOC: Remove extra # from url in fit.
DOC: Make the comment slightly clearer
Merge pull request #3800 from MechCoder/unknown_transform

Handle_unknown option to OneHotEncoder
COSMIT: Minor opt in pairwise_distances_argmin_min
OPT: Speed improvements by avoiding repeated calls to check_array
Merge pull request #3811 from MechCoder/fix_repeated_checking

[MRG] Fix repeated calls of check_pairwise and type casting in pairwise_distances_argmin_min
ENH Add cross_val_predict function

This function returns the cross-validated prediction for each element in
the input data (i.e., the prediction that is made when that object is in
the test set).
FIX score precision in doctest
Implements Multiclass Hinge loss
Merge pull request #3779 from arjoly/sw-dummy-regressor

[MRG+1] Add sample_weight support to Dummy Regressor
Update what's new
FIX #3503: use linalg.pinv to better deal with singular input data
Fix using ground truth in silhouette score in document clustering. Closes #3806.