New Query Options tray added

For scope, see: https://issues.apache.org/jira/browse/COUCHDB-2347

Two important things to mention:
1. The "Compact View" button has been removed. I want to discuss with @seanbarclay about whether it should really appear in the tray.
2. There's an outstanding issue (outside this ticket) where the header bar doesn't always show the correct content when navigating from page to page.
By convention we normally use `_.extend` or `_.defaults` http://underscorejs.org/#defaults. But if they don't fit here then I'm happy to use `$.extend`