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.~~

Both of these are now fixed in this PR.