ALLJOYN-549 Added support for annotating an object as secure.

This doesn't change the wire protocol just handles the tracking and
triggering of authentication based on object security.  Interface
security still applies.

org.alljoyn.Bus.Secure can have three values:
   true == AJ_IFC_SECURITY_REQUIRED
   off  == AJ_IFC_SECURITY_OFF
   inherit == AJ_IFC_SECURITY_INHERIT

When security is required the annotation must stay 'true' for backward
compatibility with old interfaces.

This includes a suite of unit tests to verify the object level
security.

Change-Id: Ibbb84c305ed923dbc915d4be5cacbbe1da97e0a5