Useful class to parse the query. (We should have had this class years ago).
This class replaces all replicated code about how to parse a String query into
a Query tree, and add it to a pre-existing search request. This is most often
called from Manager.newSearchRequest(String,String), although client code can
use this method when other forms of Manager.newSearchRequest() are used.
Note that this class throws QueryParserException when it gets upset.