added filter to handle an IP loopback message in CA directly

added filter to handle an IP loopback message in CA directly

If IoTivity stack sends a message to itself, which means the loopback,
it is unnecessary to let them go through the socket layer.
Especially it is a waste when the large payload will be sent by block-wise transfer.
So I made CA layer to handle the loopback message directly.

Change-Id: I2b8e5217575df391dd4ab66d924a3a24c2584915
Signed-off-by: Jaewook Jung <jw0213.jung@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/12887
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Phil Coval <philippe.coval@osg.samsung.com>
Reviewed-by: Hyuna Jo <hyuna0213.jo@samsung.com>
Reviewed-by: Jaehong Jo <jaehong.jo@samsung.com>
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>