* Fixed bug that would cause the renderer for sprites to be corrupted on when the sprite vector is resized
* Changed deleted_sprites variable to deleted_animation in sprite object
* Changed sprite pointer vector to sprite id vector in canvas object
* Changed the value stored in Fixture UserData pointer to sprite id rather than sprite pointer because pointer would change on resize anyway
* Added some new physics functions
* Added new documentation
* Added some auto checks for OS to rc_os_defines.h
* Fixed bugs on settting and getting position of sprites
Finished documentation on sprite physics and joints
Fixed some bugs in sprite physics
Added safety checks for joint types
Added code to free up joints when a canvas is destroyed
* Finished working on tiling
* Changed how sprite layers work. Sprite layers are now not confined to the limits of the actual canvas but instead will decide where to draw each sprite based on the canvas offset and the sprites location
* Rewrote the actor animation system to work like sprites
* Renamed a few functions
* Added DeleteSpriteAnimation() and the delete queue to sprites
* Removed transitions for the time being (they don't seem to work in irrlicht right now
* Added PreUpdate() function
* Added documentation for name changes and new functions
* 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
