Fix scope target, remove redundant code

[NikitaDudin]

I faced with issue of wrong camera initial position on next 3d-scene creating after using enabledPan and change positions with panning on first/previous scene creating iteration.

partialScope object uses on creating a new instance of the orbit controls. But partialScope.target value not recreates on resting partialScope object because it is object(just copy link to Vector3 instance). This can lead to conflicts when using multiple instances at the same time because they will all reference the same target object.

maybe fix it #31

[TiagoCavalcante]

Thanks @NikitaDudin!

There is just a small problem: the types are inferred from partial scope. I'll merge this and fix it in another PR, then release a new version.