FIX: random_start feature in GaussianProcess
FIX: gp_diabetes_dataset examples (theta_ attribute)
DOC fix formatting of attributes etc. in docstrings
DOC move Attributes section to after Parameters and style likewise
Add sample_weight parameter to metrics.jaccard_similarity_score

 - Include this metric in sample_weight test in tests/test_common.py
ENH Sparse multilabel target support

All multilabel metric calculation is now performed efficiently over
sparse CSR matrices.
DOC label indicators are clearer as ints than floats
DOC more precise input type for multilabel metrics
MAINT use assert_warns
MAINT Fix regression random projections work sparse matrices
DOC whats_new.rst: missing backported fixes for 0.15.1
fix: i might be undefined
FIX six issue with module imports

Fixes #3518, #3519.

Inspired by Johannes Schönberger's patch to scikit-image,
https://github.com/scikit-image/scikit-image/commit/71743d2d6ff3666c9530278dfd650c2435fa15d9
Max iter param in Liblinear is now softcoded
ENH: Return n_iter_ from liblinear and print convergence warnings
TST: Added test to check ConvergenceWarning
Update plot_tree_regression.py

Import statements have been moved to the beginning of the file.
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