FIX numpy 1.3 issues with multilabel metrics
Update load_svmlight_file docstring.
Merge pull request #1741 from arjoly/metrics-fix-np-1.3

[MRG] FIX numpy 1.3 issues with the new multilabel metrics
TST compute_class_weight in utils
FIX + TST + DOC compute_class_weight

Fixes #1746, #1747. Bug reported and fix proposed by @gatagat.
ENH use bincount in compute_class_weight

As suggested by @amueller.
BUG use fixes.unique
FIX compute_class_weight edge case