Server sends 304s to Studio when necessary. Keyboard shortcut fixes. Navigation bug fixes. Editor focus fixes.

The server was not properly parsing etag headers when getting requests from the Studio for JS and CSS files. In particular, the values it was getting back contained beginning and end quotes. Thus, the date comparison check failed, thus always sending 200 OK and never 304 Not Modified. This is a big performance fix for the Studio, especially felt when running the Studio remotely.

I also fixed several keyboard shortcut and focus issues. When saving docs or running queries via keyboard shortcuts, we were stealing focus from the editor, disrupting the user's workflow. That's fixed. 

Also, some page keyboard shortcuts wouldn't work unless a particular control was focused. That also is fixed.