PCAModel can be built from a generator
Merge branch 'rm_dgemm' into pca_generator

Conflicts:
	menpo/model/pca.py
switch transposition order in pca so we don't flip
inplace dot left and right, tests
use inplace dot if inplace in pcd, test inplace
clarify docstring on PCA
Merge remote-tracking branch 'upstream/master' into pca_generator
only demand allclose on inplace dot
Merge pull request #518 from jabooth/pca_generator

PCA memory improvements, inplace dot product