[feature] Merge new range index branch into develop

The new range index is a complete replacement for the old index. It is based on Apache Lucene 4.4.0 and has been in testing for several months. It is faster, supports more optimizations and scales much better than the old index. In particular, the dependency between collection size and update speed has been dropped, thus removing one of the last severe limitations in eXist.

Since the new range index is a completely separate module, it can co-exist with the old index, thus allowing users an easy migration. To distinguish between the old and the new index configuration, configuration entries for the new index have to be wrapped into a <range> element in collection.xconf. For examples, see the XQuery smoke tests in extensions/indexes/range/test/src/xquery. Documentation will soon be added to the documentation app.

This pull request also updates Lucene to version 4.4.0, which involved a major redesign. Lucene 4.4.0 offers better indexing and query speed. The overall architecture has changed quite a bit, resulting in a massive overhaul of eXist's Lucene integration.