Ogre Instancing: Fix broken logic in finding existing instance and mesh targets with ref and submesh. Fix that meshes that are set as static also create new instances (with all of its submesh/material combos) as static. Added a getter for static instancing for a particular mesh ref.
Ogre Instancing: Fix example scene script to new function name in OgreWorld.
Ogre Instancing: Merge VS and PS warnings to a single warning, this will usually override both or none so this makes the output cleaner to read. Fix documentation that CreateInstance can return null in error situations with given input.