Shorten Util func names, move some functionality into Util from Site
Move options handling into Model where it belongs
Move user login functionality + db utils into Util
use minimized d3.js
Move REST snap handlers into the REST module
Add a "remember me" field into the user login screen

Note that the 'value="1"' part in the checkbox input is due to
https://github.com/snapframework/snap/issues/96 - AFAICT it shouldn't
be necessary.