Remove the use of triplot

Use the the PointGraph viewer instead of triplot because triplot
has some weird behaviour where it resizes the image and looks
terrible.
Show the path in the image widgets
Fix how images are converted to PIL

Can now support float32, float64, bool and uint8 images. uint8
images are untouched, the rest are converted and scaled by 255.

Floating point images outside of the range of [0, 1] throw an
exception now
Stop printing so many 's's!

Thanks @trigeorgis!
convert dgemm calls to np.dot
small tidying to PCAModel constructor
Merge pull request #515 from patricksnape/path_widget

Show the path in the image widgets
Merge pull request #516 from patricksnape/as_pil

Fix how images are converted to PIL
Merge pull request #514 from patricksnape/trimesh_view_fix

Remove the use of triplot
fix bad dgemm to project conversion
Merge pull request #517 from jabooth/rm_dgemm

remove dgemm calls (replace with np.dot)