vtd-xml 2.5 released

* Added separate VTD indexing generating and loading (see http://vtd-xml.sf.net/persistence.html for further info)
* Integrated extended VTD supporting 256 GB doc (In Java only).
* Added duplicateNav() for replicate multiple VTDNav instances sharing XML, VTD and LC buffer (availabe in Java and C#).
* Various bug fixes and enhancements.