Optimizing range constraints

[Mike Klaas]

Tim Sturge posted a nice optimization for range constraints/filters  
(e.g. "age:[10 TO 35]") here:

https://issues.apache.org/jira/browse/LUCENE-1461
It has a natural applicability to Solr's fq range filters, which can  
be abysmally slow for large ranges.  Could be an interesting project  
for contributors who love optimizing speed (100-fold, in this case)  
<g>.  I'd definitely do it had I the time.

-Mike