Need to be able to set the request handler

[elyograg]

SolrJ lets you set the request handler used for a particular query, if you need to use something besides /select. WebService::Solr does not.

http://lucene.apache.org/solr/4_8_0/solr-solrj/org/apache/solr/client/solrj/SolrQuery.html#setRequestHandler%28java.lang.String%29

In Solr versions before 3.6, the handleSelect parameter was set to "true" in the example config. This meant that you could send a "qt" parameter to change the handler being used.

Since 3.6, this way of configuring Solr is deprecated. All handlers are now expected to have names starting with a forward slash, which makes it possible to use them in the actual URL. A handler named "/select" will normally exist in a typical solrconfig.xml file. The big reason this change was made is so that you can't send a request to /select, set the qt parameter to "/update", and therefore change the index even when normal access to the /update handler is somehow blocked.

In the current code for this project, "/select" is not a single string. The forward slash is separate. In solrconfig.xml they are together. To match user expectations, this feature needs to work if "/other" (including the foward slash) is sent in as the handler name. If you want to include magic so that simply sending "other" will also work, that's fine.

[elyograg]

An obvious followup -- make it possible to change the handler for update requests as well as queries.