samples/zoap_server: Add support for messages with token

So the sample zoap server application is more conformant, include the
token from the request, if any, in the response.

Change-Id: I5aacc1a3f81ebeaf473d327163c952b829489b01
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
1 file changed