updated description

Change-Id: I9c530fca78b5d7800609998b3500474ba4843a9e
added debugging code

Change-Id: I6cb01e000c36300cb0e52617825a45c4b31cbf7e
CallbackJuggler is now an ILinkableObject and registers its target as a
child.
This fixes the bug where objects using CallbackJugglers were not
reporting busy status correctly.

Change-Id: I0893a1bc513ba83678af9f559cca07303b3c96ce