EGL support: Add EGL virtualization support to glproxy.
Also, - Removed the "automagic" best renderer detection, as it needed to start both EGL and GLX which caused problems on some systems. It will return, but in a more application-controlled way. - Now it's necessary to pass the current display to the extensions helper functions, as using an internal one caused NULL being returned as the extensions string in some systems. - A lot of code clean-ups.