@Ashfurrow => support offline mode

Figured you'd want something more stable to work from, got it nearly green but I have a :ru: :airplane: to catch so there's still 3-4 reds in there. Feel free to take a look, they seem to be weird snapshot things or `rac_commands` not doing what I'd expect.

Otherwise this PR adds an offline overlay. It allows showing the help over the to top, and disables the register button. It would show behind the overlay anyway.