ALLJOYN-1956 Unit test now have error checking for object paths

The unit test were not checking object paths because of an error
in alljoyn_core now that the error has been fixed the unit tests
can check for valid object paths.

Change-Id: I77cdf4ac72793a07bd9c6b84268d49289f3ff892
Expanded implementation of MsgArg Class

Changes and additions
  - AllJoynTypeId  is now public.
  - constructor that can initialize the value in the MsgArg.
  - operator==
  - operator!=
  - Equals method for objects and MsgArgs
  - GetHashCode method
  - ToString method
  - HasSignature
  - Clear
  - Stabilize
  - TypeId Get method

Fixed a few errors reported by Doxygen

Change-Id: I41151fae7e9a7dee9628fcbabb510c8e282f414b