Update draw_PCA to draw_components
Update draw_PCA to draw_components

Address issue #152

Update draw_PCA and the axis labels to draw_components in order to make
the plot more general to other dimensionality reduction techniques like
TruncatedSVD.

awhite40/pymks,davidbrough1/pymks,fredhohman/pymks,XinyiGong/pymks,davidbrough1/pymks