STY Simplify and avoided numpy warnings in imputation
ENH/TST remove unnecessary sorts and complete testing for sparse median
COSMIT Remove unnecessary assertion
FIX for numpy compatibility, code clarity
Implemented a check for ndim exceeding two in the utils.check_arrays function
ENH: Speed up sparse_coordinate descent
Fix silhouette score n_labels

Fix such that silhouette score raises error
when n_labels is incorrect
Added number of labels for debug and regexp in test
FIX stability in HMMs

ValueErrors occur when there is 0 or nan in the covars of the data, or an
infinity in stat['trans'].
Removed unnecessary variable n_dim in utils.check_arrays, removed unnecessary parens in same place
Replaced cython calls for dot operations with BLAS calls
Trivial change in utils.check_arrays from > 2 to >=3 in attempt to rebuild Travis CI
Merge pull request #2938 from jnothman/clean_impute

[MRG+1] some clean-up in Imputer, particularly in calculation of sparse median
FIX for early numpy where astype(..., copy=...) unavailable
Merge pull request #2958 from hamsal/check_arrays_n_dim

[MRG] check for ndim exceeding two in utils.check_arrays
MAINT remove some deprecated stuff
MAINT final occurrence of "Scaler"
Fix typo in linear_model documentation
Merge pull request #2960 from ethanwhite/docs-typo

Fix typo in linear_model documentation
Speed up using typed memory views