SolrTextTagger - Issue 10:

* Renamed "Paths" to "PhraseBuilder"
* Renamed inner class "Path" to "Phrase"
* PhraseBuilder can now be reused. This allows to create one instance per analyzed label. Now a single instance can be used to analyze all labels.
* use IntsRef[] instead of Collection<IntsRef> for returning the results (to avoid creating collection instances)
* changed log.info(..) called within log.isTraceEnabled() to log.trace(..) calls
* added files created by debug level TaggerFstCorpus calls to the gitignore list.