Changes to sprite animation system

* Changed the names of some of the functions
* Added functions for setting and returning the projection matrix of the active camera
* Added a function for getting the 2D screen coordinates from a 3D vector
* Added documentation for all the new functions

rcbasic_runtime/rc_gfx_core.h

@@ -316,6 +316,9 @@ struct rc_physicsWorld2D_obj
 #define RC_CANVAS_TYPE_3D		1
 #define RC_CANVAS_TYPE_SPRITE	2
 
+#define RC_PROJECTION_TYPE_ORTHOGRAPHIC		0
+#define RC_PROJECTION_TYPE_PERSPECTIVE		1
+
 struct rc_canvas_obj
 {
     irr::video::ITexture* texture;