Underpass A3

-Added more new graffiti
-Added player markers that show when there's 60 seconds left on the clock
-Added temporary music for the countdown and jail cell (Splatoon 1 - Now or Never and the Wii shop channel banner theme respectfully)
-Updated misc geo
-Fixed a bug with the jail cell door that could allow players to prevent it from opening
-Detailed a bit

Added some temporary graffiti and a basic 3d skybox

Fixed some logic issues with the cells and updated them to a more recent design.