ENH: add fast_dot function
employ DataConversionWarning
FIX: avoid zero-dvision warnings
FIX: fix test warning
better handling of warning in test
COSMITS
FIX: workaround for missing BLAS
ENH: return np.dot if ndim does not match
CLEANUP
FIX: remove spurious test
ENH: add fast_dot shape check
ENH: cover another cornercase + fix messages
ENH: add new Warning class, improve tests, update docs
FIX: superfluous check
ENH/DOC: add performance tips on fast_dot
COSMITS
update what's new
FIX: proper doctest
ENH/FIX: address @ogrisel comments
FIX: move inline comment to its right place