Large changes for fbdev support.

Change from DIRECTCOLOR to TRUECOLOR, and enable
support for PSEUDOCOLOR. DIRECTCOLOR support needs more work.

Add the ability to change the mode on the fbdev device.

Support depth 8, 15, 16 and 24 (and 32).

Add a /dev/fbX device per CRTC, but there's some code which
doesn't allocate the fbX device unless the output is actually
enabled. Read the code on this as it impacts the fbcon map flags.

Pick CRTC's based on the available outputs. More work could
be done here to match modes, so cloning could be achieved on
outputs. This fits more inline with what the X code does.