Add Generic Event extension to nx-X11/programs/Xserver

[sunweaver]

We should start working on including GenericEvent support in nxagent:

commit 5e439109292e54b5c4d1a7bc7b6ac0e42ee285f7
Author: Peter Hutterer <peter@cs.unisa.edu.au>
Date:   Mon Apr 30 12:57:42 2007 +0930

    Add GenericEvent extension to Xext.
    
    This adds (unconditional) support for the GE extension. Anything from now on
    that sends events in MPX will have to use the GE extension. No GE, no MPX
    events. GE is not actually used yet from anywhere with this commit.
    
    You will need to update x11proto, xextproto, libX11, libXext and xcb to the
    matching xge branches. Things will _NOT_ work without the updated protocol
    headers and libraries.

[sunweaver]

I have worked on this today. Fix is pending...

[uli42]

One application using the GenericEventExtension is atom. I have tried with this path today and atom does not work but crash weirdly... Also nxagent is behaving strange, w.g. you can run nxagent :55 and open an xterm on that server. But you can not enter any keys before also running window manager. Without this patch that's working fine. Also mouse events do not seem to work.