FIX ensure that pipeline delegate classes_ to the estimator
pep8
TST bagging of pipeline of classifier
DOC update what's new
DOC: Document criterion_ attribute in LassoLarsIC
Merge pull request #3740 from MechCoder/lassolarsicattribute

[MRG] DOC: Document criterion_ attribute in LassoLarsIC
DOC for the Git novices: cd to the clone directory
MAINT remove integer warnings under Python 3 + numpy 1.8+