Make ModelNode and Light as Control

Make ModelNode and Light as Control

Since we need to use some control features (like KeyboardFocus) let we make
ModelNode and Light as Control, instead of CustomActor.

TODO : We'd better make some universion Control for Scene3D.
For example, we should not allow to add Visual into ModelNode or Light.

Change-Id: I8acbb57d967c438101fe8a1877950d044ca943f2
Signed-off-by: Eunki, Hong <eunkiki.hong@samsung.com>