modifications to use frange for facet queries

for facet queries, use of the solr frange function provides a [performance enhancement](http://heliosearch.org/ranges-over-functions-in-solr-1-4/) over using interval notation ([0.0 TO 5.0]). additionally, this opens the possibility for users to override blc_facet_range to make use of functions for the facet query "field". an example would be the use of geodist for geolocation searches. one could then create the facet query: 
{!key=loc_c_300:3000 frange incl-false l=300.00 u=3000}geodist(loc_c,32.946467,-96.786969)

additionally, changed the facet queries to make use of the "key" tag. this allows the result to be more easily identified

removed references to "tag" and "ex" because they were not being used as designed by solr and were therefore being ignored by solr