contain all tinyfx state and defer all api resource creation until tfx_frame

[shakesoda]

subset of #18 and perhaps #23 - it'd be very helpful to be able to build everything the frame needs in game logic thread and just send that back to the render thread to process while you begin the next tick.

for this to work, all tfx calls need to be able to work without being on the gl context thread except for things like set platform data, reset, frame, etc... haven't worked out the details yet, particularly with resource creation and tfx_set_uniform*