DOC: Simpler cross-validation iterator doc
2-fold => 2-fold cross-validation
approximately the same percentage of samples
Remove spurious print statements in sample snippets to make the doc easier to follow
Lowercase y and more consistent blank line usage
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