Add some new functionality to our xorg detection routines.

Now when xorg fails to start with its own internal detection, we will attempt to
detect a second pcivga card, and tell X to use it.

This fixes an issue with Xorg not starting on some weird optimus / hybrid laptops where the secondary
video card is the "intel", which *does* work, but the primary is the AMD/NVIDIA card which cannot function
in discrete mode...