(core+platform) cutting down on the video_display

The legacy global arcan_video_display was evicted
from being directly referenced in the platform
layers as another step towards covering all the
inter-process buffering sharing cases.

-a multisample argument died in the process,
for platform that supports it, it has been moved
into environment variables.
(platform) added nvidia-egl stubs

Added a rather stubbed / worthless egl-nvidia
backend. The plan for this backend is to support
the approach suggested by artiger@xdc2014 in
regards to how X- less GL could be set up.

The current show-stopper for working with this
further seems to be driver support though,
the latest beta drivers doesn't present me with
anything other than CUDA devices and without
working KMS I'm still fumbling blind
Added a rather stubbed / worthless egl-nvidia
backend. The plan for this backend is to support
the approach suggested by artiger@xdc2014 in
regards to how X- less GL could be set up.

The current show-stopper for working with this
further seems to be driver support though,
the latest beta drivers doesn't present me with
anything other than CUDA devices and without
working KMS I'm still fumbling blind..