* Fixed SkeletonJson not allocating enough memory for curves (maximum of 6 curves/key, not 4). Fixes email: FMfcgzGkbDfvckWcFxWlsTWzFhMXsTDw
* Removed SkeletonData and Skeleton methods: findBoneIndex, findSlotIndex. Bones and slots have an index field that should be used instead.
* Removed SkeletonData and Skeleton methods: find*ConstraintIndex. Only SkeletonJson needed these, they don't need to be in the public API.
* Used a local for number of frames where it was used many times.
