[xliff] working draft for 1.1

Hi everyone,

Attached a early working draft for the 1.1 specification. This is based on
1.0, with some of the possible changes already integrated in the
specification. Deleted text is red, added is green, notes are in yellow.

The section about Changes list also some of the various topics we are still
discussing or will or have been based on all the discussions since the
face-to-face meeting. Those are just working notes.

The draft section on Extensibility is not finished, but some of the ideas
and mechanism are outlined there already.

Obviously none of those items is final until we vote on it at some point.

I'll try to have the clean XSDs corresponding to 1.1 by the meeting after
tomorrow.

cheers,
-yves