Allows the ability to override and use partial range RGB with the
DirectShow and Decklink device sources when partial range RGB is
implemented. Fixes certain cases where devices could capture RGB in
limited range via HDMI (per the HDMI specs).
LGP devices are devices that induce anger in any sane developer because
they're prone to bad audio timestamps when using their decoded data
directly. For that reason, add a hack that smooths the timestamps
within a large threshold to prevent audio skipping.
