ENH: Call plot twice per class label rather than for every point.
ENH: Call plot twice per class label rather than for every point.
Merge branch 'plot_dbscan' of https://github.com/ericjster/scikit-learn into plot_dbscan

Fix formatting to be PEP8.
Merge pull request #2502 from ericjster/plot_dbscan

ENH: Call plot twice per class label rather than for every point.
MAINT add authors to validation.py and pairwise.py
MAINT: use python setup.py clean in Makefile
FIX parallel FeatureUnion.fit and fit_transform

It didn't work previously because transformers were fit in another
process, and information they learned was not transferred back.
DOC docstring for extmath.norm