Changed if/rt to be space-delimited strings in CBOR encoding

Changed if/rt to be space-delimited strings in CBOR encoding

The Spec says that if/rt should be space-delimited values rather than
just an array of strings, so this changes all encodings of if and rt to
be space-delimited.

Also adds some unit tests to validate the defensive nature of this
reading.

Change-Id: Iebd1d5a215a06abb023bb1b33112dac1df3511a1
Signed-off-by: Erich Keane <erich.keane@intel.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/2645
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Patrick Lankswert <patrick.lankswert@intel.com>