Handle non-power-of-two textures for older cards that can't handle NPOT textures.

This requires additions to GenericMath for checking npot.

Signed-off-by: Nick Minkler <sleaker@gmail.com>
Use a shared class for VertexData rather than trying to split it into multiple types.

DataLists can be stored on the model for non-GPU vertex data, and re-pushed to the attribute as necessary as model data shouldn't be changing often.

Signed-off-by: Nick Minkler <sleaker@gmail.com>
Merge pull request #7 from Sleaker/master

Simplify how VertexAttributes are handled.