Added upgrading

--Woot woot
--Currently prevents you from rotating basic beacons - gotta add ways to
do this
Added ability to rotate basic towers (again)

--To rotate basic towers, hold button AND STICK in direction other than
beacon facing
--To upgrade basic towers, hold button while facing direction beacon is
facing
--Right now, doesn't do anything if you hold button but not the stick
while facing direction other than beacon is facing