Added support for CBOR content format option.

Added support for CBOR content format option.

Added a new option defining content format for CBOR encoded payloads.
This will allow a more robust interpretation of incomming payloads
and will also permit generic stacks that have no apriori knowledge
about OIC to interpret the payloads going accross the network.

Change-Id: I34feb4e305458fcef4e7343cda313d9a52d12046
Signed-off-by: Stephane Lejeune <stlejeun@cisco.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/2262
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jon A. Cruz <jonc@osg.samsung.com>
Reviewed-by: Hauke Mehrtens <hauke.mehrtens@lantiq.com>
Reviewed-by: Patrick Lankswert <patrick.lankswert@intel.com>