Beta Build 5

New Enemy Type: Spawner (On Death adds 2 new generic bugs)
New Sound: Spawner Pop
New Graphic: Tower
New Graphic: Bug_Shooter Projectile (w/ Class)
Bug Fix: Tower fire at empty target
Bug Fix: GUI now releases selected tower.
Bug Fix: Towers now render properly with tile underneath.
Constructor change: All TOActors are now responsible for their own
texture. Define it in the constructor.
Bug Fix: Health bar now renders properly