Adding TokenFilter support:

This adds the "LookupAttribute" used by the Tagger to decide if a Token consumed via TokenStream#incrementToken() needs to be looked up in the FST corpus. Analyzer chains may define a TokenFilter component that does set this attribute to TRUE or FALER. Typically this will be done based on NLP (Natural Language Processing) results.

The Tagger uses the LookupAttribute as follows:

* Tags are only created for Tokens where the LookupAttribute is TRUE
* Advancing tags are continued regardless of the LookupAttribute value
Changed the TaggerFstCorpus class to be public
Merge branch 'master' of git://github.com/westei/SolrTextTagger into westei-master
updates to the "LookupAttribute" (now TaggingAttribute) [SolrTextTagger Pull request 7](https://github.com/OpenSextant/SolrTextTagger/pull/7) based on feedback of [David Smiley](https://github.com/dsmiley)

* renames Lookup** to Tagging**
* adds a unit test for the TaggingAttribute
Merge branch 'master' of https://github.com/westei/SolrTextTagger into westei-master
Small refactor: rename "lookup" to "taggable"
Reformat indentation (2-spaces)
Merge branch 'westei-master'