AJCORE-314 Build the alljoyn_unity_native library

Due to the change AJCORE-269 the bundled daemon is no longer
built into the alljoyn_c shared library this will build a
shared library alljoyn_unity_native that will contain the bundled
daemon.  The unity bindings assume that the bundled daemon is
built in with no additional linking.

Change-Id: Iaf4eb0a21d3e119a6a16c544075f8cb4676754dd