ITS module implementation

Hi all,

Based on the recent discussion about the namespace(s) for the XLIFF module, I've worked a bit on Okapi's on-going implementation.

There is a new snapshot here:
http://okapi.opentag.com/snapshots/okapi-xliffLib_all-platforms_1.1-SNAPSHOT.zip

It implements part of the ITS module using the namespace URI "urn:oasis:names:tc:xliff:its:2.1" for all elements and attributes of
the module (e.g. annotatorsRef, mtConfidence, domain, etc.)

The documents it creates are version="2.1" by default, but it should be completely backward compatible on XLIFF 2.0 documents.

Feedback welcome as usual.

Cheers,
-yves

PS: If you need a stable implementation of 2.0 use:
https://bintray.com/okapi/Distribution/Okapi_XLIFF_Toolkit/1.0/view