multi-use invites will have a set limit of how many times they can be
used. They can also be set to have no limit. An additional menu is
planned for multi use invites to see when they have been used, and by
who.
The admin can switch between the two default themes without a page
reload, with a nice animation (on small screens). Preference is stored
as a cookie, so the default theme setting will still apply to others.
