MAINT faster test_weight_boosting
TST speedup test_spectral_biclustering
TST faster check_transformer_pickle by fixing n_iter
TST speedup test_permutation_score

Also remove a warning with fbeta score that had non enought samples of
a specific class by chance.
TST remove joblib tests from sklearn
Tidy up by removing unnecessary local variables
Merge pull request #3414 from lesteve/scheduled-removal-from-0.15

[MRG] Tackle remaining comments in #3411
Merge pull request #3403 from ogrisel/speedup-tests

[MRG] Make tests faster to run
ENH add sample_weight support to dummy classifier
ENH don't convert dataframes in grid search and cross-validation
Merge pull request #3418 from arjoly/dummy-weight

[MRG] ENH add sample_weight support to dummy classifier
DOC update what's new
DOC sample_weight attribute
FIX: Remove raw_coef_ attribute that eats up memory
Modified sparse OvR to handle sparse target data

Defaulted label binarizer to set sparse_output=True when training ovr
classifiers, edited Label binarizer to allow for sparse binary column output
DOC fix docstrings; add @hamsal to authors
split test_common.py into checks and test file.
move dataset generation into estimator_checks
Remove 'DeprecationWarning: using a non-integer number instead of an integer will result in an error in the future' warnings
Closes #2360. Fix tiebreaking.
some cleanups in common_test, speedup.