Made creep_spawner inherit from Creep

Basically, now they can take damage and spawn creeps on death, and
anything else a creep can do.  Also made spawners magenta (minimap is
drawn with color not texture)
explanations of the changes
Merge branch 'master' of https://github.com/Phateus/SpiderKiller

Conflicts:
	Project2/Projectile.cpp
	Project2/Scene.cpp
	Project2/creep_manager.cpp
	Project2/creep_manager.h
	Project2/creep_spawner.cpp
	Project2/creep_spawner.h