Added hitbox-point collision functions (Hitbox.h, Sprite.h)
TestWorld.h will now be a hub for accessing different developers' different test worlds. (TestWorld.h)
Added a button class, which has to be subclassed in order to do anything when clicked. (Button.h, Button.cpp)
Added a bunch of developer test world button images.
Merge branch 'master' of https://github.com/zebbedy/jcc2d