Removed buffer swap from doFrame function.

Clients must manually swap buffers. This is to support reading straight
from the current frame buffer in the batch renderer.
Building initial triangle unit / perceptual diff test.

Basic triangle (2 in this case) geometry built. Need to test renderer by
access OpenGL framebuffer and extracting image after render.
Make batch renderer resolution square.

All golden images will be 600x600 in resolution.
VBO and IBO creation now supported.

Also fixed a bug in the persistent shader loading code.