Added underground section, created collision boxes

Added the actual underground map and created all collision boxes that
are required.

Currently bullets cannot shoot through water since water is just made up
of collision boxes so you have to change that.
Bug fixes: bullet drawing, portal use

Bug: bullets draw even if they're on a different floor.

this has been fixed so bullets only draw if they are on the same floor
as the player.

bug: when using portals to go between floors sometimes it makes you
stuck in a wall

this has been fixed. the problem was that after the server changed the
player's floor with the portal, the client would send a position update
before the server could send a floor update so the player on the server
side would be moved to the client's position which would be inside a
wall.

now the server ignores client position updates if the client's floor is
not the same as the server's floor.
saved bullet file