Added LibXML2 to CMake
Changed sprites and backgrounds PHYSFS paths
Added /sprites to PHYSFS
Parsing Sprite definitions from XML
Added reference pointers
Added globals header. This should be removed as soon as someone finds a good solution
Added dictionary
Added initial texture stuff
Made init code initialize SDL globals
Made sprites load textures and set up frames
Fixed bug in refptr
Fixed small bug in refptr
Added tests for refptr
Changed sprite code to return RefPtr
Fixed small bug
Added DrawSprite