Renamed variables and functions of Notification consumer.

Renamed variables and functions of Notification consumer.

a couple of variables and function is renamed.
in particular, processing function of queue task in each submodules renamed
to TaskProcessing and thread structure is renamed to NSThread from NSThreadHandle.
and thread join function is added.

Change-Id: Id1508e3f6422318f316ee388cf195217d0823ebd
Signed-off-by: KIM JungYong <jyong2.kim@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/8379
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>