Solr 4.4 support (without breaking support for earlier versions)

This adds support for Solr 4.4:

Solr 4.4 introduces some API changes that do affect the SolrTextTagger. However tests revealed that those incompatibilities are only on the API level. Function wise Solr 4.4 is still fully compatible to earlier 4.+ versions.

Because of that I decided to use reflection to hide API incompatibilities. This allows SolrTextTagger users to use both Solr 4.4 and older versions (I can verify that Solr 4.2.1 works fine but in principle all versions >= 4.1 should work).

Because of [LUCENE-4963](https://issues.apache.org/jira/browse/LUCENE-4963) checks for `posInc > 1` are commented for both `Tagger` and `TaggerFstCorpus`. Doing so makes all unit test happy for both Solr 4.3 and Solr 4.4.