Resolved UnityEditor Build Errors

There is a lot of editor specific code that was causing errors when you
build. All Editor specific code has been surrounded in #if UNITY_EDITOR
selectors to allow this to compile.
Added class to create polygons from bitmaps.
Merge branch 'master' of https://github.com/mjholtzem/UnitySpritesAndBones into mjholtzem-master
Some fine-tuning of the conditional compilation.