Merge pull request #618 from bvssvni/master

Added DeformGrid
Merge pull request #621 from bvssvni/master

Added drawing of deformed image
Merge pull request #623 from bvssvni/master

Added inverse lookup
Merge pull request #624 from bvssvni/master

Changed to uint for safety
Use local variables for fr in deform

Closes https://github.com/PistonDevelopers/graphics/issues/626