Automatically remove eye-candy when connecting with VNC, FreeNX, etc.

Connecting with FreeNX or VNC is a common task for sysadmins, and a growing use case for home users who connect to their home machines from work. These protocols do not perform well with fading, shading, transparency, shadows, etc., and they are completely incompatible with fancy XGL and Aiglx. Remote sessions should be flagged as such and drop to a lower level of eye-candy. This could be on or off, or depend on connection speed, but in any case, hardware accellerated rendering would have to be disabled.