Update README.md

[Readme] Note about Spine-Unity when using large atlas images.
spine-c: inherit scale and rotation implemented. Allow to parse latest JSON.
Merge branch 'origin/master'
Fixed renderer colors.
Added missing files.

closes #117
More efficient draw order when bind pose order is keyed.
Keyable draw order for spine-c.
Additive blending for spine-sfml.
Bounding boxes for spine-c and spine-sfml.
Renamed ComputeVertices to ComputeWorldVertices.

Sorry for the API breakage, but this is line with UpdateWorldTransform, BoundingBoxAttachment, and future attachments.
Simplified SkeletonBounds AABB computation.
Renamed Polygon struct.
spine-cocos2dx now compiles with latest spine-c.
spine-cocos2d-iphone compiles with latest spine-c.
update convenience constructors for CCSkeleton, CCSkeletonAnimation
Inherit scale/rotation and additive blending for spine-as3 and spine-starling.
Inherit scale/rotation and additive blending for spine-js.
Fixed alpha in spine-xna.

#121
spine-xna no longer premultiplies alpha on load. Do it when packing the atlas.

This is just simpler all around. The renderer has a setting to know if premultiplied is being used. #121
Merge pull request #118 from slow-banshee/master

update convenience constructors for CCSkeleton, CCSkeletonAnimation