SolrMatcherSupport configurability

[dsmiley]

SolrMatcherSupport's initialize() method currently examines global system properties to decide where it will find Solr. In general, global system properties can be handy but shouldn't be the only means of configuring things. There may be more than one Solr server being used, particularly in development (local indexing and remote gaz catalogs). This can be fixed by simply adding a setter for "solr", and then not overriding a non-null value in initialize(). Also, in the case that "solr.url" is set, it'd be better to concatenate the getCoreName() method's value to the url and with an extra '/' so that if I use a solr.url system property then I can have, say, both the "gazetteer" and "tax" cores and still use one solr.url set to http://..../solr/. Otherwise I can't use two SolrMatcherSupport's for remote'ed Solr.