Added AnimationState clear.

id return value for factory methods.
Fixed skeleton copy ctor.
isComplete for AnimationState.
spine-lua generic Lua runtime, refactored spine-corona.
spine-love, Love runtime.
Centered spineboy.
License header.
Removed old structs.
Removed convenience methods to make it clear that the spine-c API should be used.

Discussion here:
http://www.esotericsoftware.com/forum/viewtopic.php?f=3&t=536