Merged "Sign up / Login" button to new slim file to avoid duplicated code.
Added link to administration tool, currently just points to invitations list.
Fixed a bug that allowed potential infinite recursion.
Nested list of sub locations is now toggleable on click.  Will need to add expandable list icon next.
Changed styling on toggleable ul and li elements to show +/- signs before it.
Updated levels to use a select (1-40) and allow "Unspecified", which renders as "?".