Adds group support to the core search API and the Solr search engine.
This allows for:
* User searching by group (in the API only, no interface yet)
* Automatically restrict search results by group (in some cases like
separate-groups forums)
- Silents the system call when no correct data provided
- Converts long exception messages to standard server
error + debugging message with the exception
Also removing is_server_ready call from execute_query as in production
workflows search is done through \core_search\manager::search and
\core_search\manager::instance already checks is_server_ready. In
testing environment setUp functions should check that the server is
ready before performing other actions.
sam marshall