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
FIX: performance.rst doctest
ENH: restrict fast_dot to  np < 1.8
COSMIT: remove unused import
FIX: ghost diff
ENH: update version checking
Merge pull request #2288 from dengemann/fast_dot

[MRG]: add fast_dot function that directly calls BLAS with appropriate data input
ENH: put fast dot to PCA, ICA and FA
FIX: test doc np.allclose
Merge pull request #2396 from dengemann/insert_fast_dot

ENH: put fast dot to PCA, ICA and FA
tree export_graphviz: remove unused close parameter and close the file if out_file is a string