ENH add label ranking average precision
DOC write narrative doc for label ranking average precision
DOC FIX error + wording
TST invariance testing + handle degenerate case
flake8
FIX use np.bincount
DOC friendlier narrative documentation
ENH simplify label ranking average precision (thanks @jnothman)
ENH be backward compatible for old version of scipy
Typo
pep8
DOC remove confusing mention to mean average precision
DOC improve documentatino thanks to @vene and remove mention of relevant labels
DOC more intuition about corner case
DOC add documentation to backported function
ENH less nested code
ENH better default for test for SelectKBest and random projection
MAINT tree compute feature_importance by default
pep8
Merge pull request #3439 from arjoly/test-commons

[MRG] Simplify test commons