Messagebox PR follow-up

 * Returning 404 on message delete when the timestamp is not found
 * Simplified checking for when a message exists or not
 * Removing unneeded compacting
 * Added INFO statement on discussion deletion
 * Added some test cases for MessageBox.deleteMessage
Messagebox search refactor

 * Search documents for messages now only have an id and body field
 * Removed custom_boost_factor from general search query
 * createStringQuery now takes a fields parameter where you can specify
   which fields you will be searching through