Implemented Custom Extensions for SpriteMaps (*.smap), Animations (*.anim) and AnimationSets (*.animset).
Also restructured Frame to be a container for SpriteMapRegions rather than an extension of them. This will enable easier access to updating them when loading SpriteMaps in the Editor.
-Renamed Sprite to SpriteMapRegion
-Updated Frame code in QURO.AnimationLibrary to use SpriteMapRegions instead of Rectangles
-Replaced Drag and drop sprite rearrangement behaviour in Editor with simpler, less buggy up/down button system
-Changed Editor's save/load format to be a MonoGame compatible Dictionary<string, SpriteMapRegion> rather than a List