Add Transform2D translation

I'm unsure of why so much code is commented out in Transform2D.

A more mature version of this module could generally be useful for doing
collision detection/modelling scenegraphs outside of the Collage interface.
Add scaleX and scaleY
Add scale and documentation for translation

Express translate in terms of the native matrix method instead.
Unify matrices to 3x2 representation.
Use s for scaling variable
Merge pull request #307 from Sheeo/transform

Improve Transform2D