XI2 ready for branching

[Peter Hutterer]

Having gone through the protocol once more I think the XI2 parts of the
server are ready for branching 1.7. Of course there are still bugs that need
to be fixed but I consider the protocol stable now. 

Over the next days I'll cut 901 releases for inputproto and libXi and finish
up some missing documentation bits. For the X server, I'll focus on
bugfixing from now on.

Cheers,
  Peter