Use subclassing from the drivers to allocate the objects. This saves
two objects being allocated for each crtc/output and generally makes
exit paths cleaner.
This splits a lot of the core modesetting code out into a file of
helper functions, that are only called from themselves and/or the driver.
The driver gets called into more often or can call these functions from itself
if it is a helper using driver.
I've broken framebuffer resize doing this but I didn't like the API for that
in any case.