BUG: reassignment_ratio == 0 in MiniBatchKmeans

And add an additonal test
Minor bug fix in metrics.adjusted_rand_score
Added tests
COSMIT translate lgamma replacement to C and clean it up
BUG: sparse center reassignment MiniBatchKMeans
BUG: sparse vs non sparse centers

The 'toarray()' method is not present on arrays
COSMIT add lgamma to gitattributes
BUG: fix test to use sparse array
DOC fix typo in LinearSVC error message
DOC: reference for discretise option
DOC update SMART notation in TfidfTransformer docs

Logarithmic tf wasn't described.
P3K: use print as a function in the examples

Also corrected some typos, including two people misspelling their own names :)
FIX make error message work when return_path=False. Btw I feel that getting "references" for numbers out of numpy arrays is pretty ugly.
TST fix random states in all dict learning tests, make test independent of test sequence.