Adds a button to enter fullscreen
当前为
⚠️ Conflicts with kklee's fullscreen button
Thanks to kklkkj for this, some code for limiting the Map Editor and Lobby's size is borrowed from kklee's fullscreen code
Adds a button in the top bar to enter or exit fullscreen - useful for map making
Fixes some bugs that were present in kklee's fullscreen by doing the fullscreen a slightly different way