DOC: minor improvement in comments of an example
Revert "ENH sparsify and densify methods for CD models"

This reverts commit ee85da8421a35894620e86dbd5b0013b5628812f;
shouldn't have been committed to master.
Merge pull request #2864 from sciunto/doc

DOC: minor improvement in comments of an example
MAINT missing import_array() in isotonic r. Cython code

Not extremely important, but issues one less compiler warning.
MAINT get rid of compiler warnings from Liblinear
BF: load_boston() return 13 features, but 14 feature names

Last column has the target value, hence only report first 13 names.