Fix error where mod was causing game to crash.

Server mods are now changeable by hosts of non-caves, non-dedicated servers. Clients will be kicked out of the server if the host makes changes to server mods. We made use of the Create() function found in servercreationscreen.lua to regenerate the world with the new mods.

Fixed duplicate connection error.
When clicking apply, reconnecting will now take a tiny bit longer since the game must have time to disconnect first.