allow multiplayer connections, without hosting
oops, bad chars got in the src
fix loading of ui, it was still pointing to my old installation subpath

which wasn't getting updated of course, and left me wondering why it didn't
change.

* main menu document takes up the full screen now, which has the benefit
that it's on top of other documents like chat, inventory, etc. and won't
allow input elsewhere.
add transparent background to main menu, make it actually fullscreen

this way input will be blocked on everything but it.