Enable Facets (field and range)
Add highlighting to full text search

Allows users to chain #highlight(...) to a
Datastax::Relation to enable Solr highlighting
when performing full text searching.

Highlight results can be found on the
Datastax::Collection#highlights method after a Solr
search respose is returned
Merge pull request #9 from cattywampus/highlight

Add highlighting to full text search
Merge branch 'facets' of https://github.com/PaulBabka/datastax_rails
Fix deprecation warnings
Fix last of the broken RSpecs
Documentation updates
Remove unused code
Doc updates and remove unneeded code