DLF,  11th April 2006   Slide 25
Extra Term Information
* Issue:  Desirable to return sub-query level details
 Eg:  How many records matched in one part of the query
* Details to return need to be extensible
* Eg: hit counts, actual query performed, suggested query,
  result-set identifier, etc.
* Solution:  Add extraTermData into the XCQL representation
 XCQL only returned in SRU response, not request