Moved ControlImpl to Internal namespace & renamed to Control

Moved ControlImpl to Internal namespace & renamed to Control

[problem]      TypeRegistry does not have an entry for ControlImpl but that is what all
               ControlImpl objects are set to when using GetTypeName() etc.
[cause]        This means we cannot use control properly with the type-registry.
               Everywhere else, the namespaces are stripped from the typeid name so for
               Internal::ImageActor we just have ImageActor and this matches the entry
               for ImageActor in the type-registry.
               However, for Control, we only have an entry for Control, not ControlImpl so there
               is no match.
[solution]     By moving ControlImpl to Internal::Control we will have the match in the
               type-registry.
               Added typedef for ControlImpl so applications will only have to be recompiled.

Change-Id: I50d63b27f0fc6af0e8de1c59757e0a9324354c63
Signed-off-by: Adeel Kazmi <adeel.kazmi@samsung.com>