OPT: Prevent iterating across n_features twice
Merge pull request #3653 from MechCoder/minor_opt

[MRG] OPT: Prevent iterating across n_features twice
DOC restructure data transformation user guide
Merge pull request #3587 from jnothman/transforms-doc

[MRG] DOC restructure data transformation user guide
FIX #3370: better lars alpha path inequality checks for 32 bit support
ENH comment on drop for good not being triggered in the tests
DOC fix broken URL

+ remove trailing whitespace
adding value error for partial fit with auto weights
adding note to whats_new.rst
removing miss-merge and adding github
adding a more descriptive error message
adding escape characters to regex
Sample weights for gradient boosting

Exponential loss for classification + predict_proba refactoring
more tests
add exponential loss to narrative documentation
cosmit: doc
raise ValueError for sample_weights and robust regression
bincount supports weights
more elegant PriorProbabilityEstimator
adressed Olivier's feedback