Changing ocstack to retrieve double instead of int using cJson

Changing ocstack to retrieve double instead of int using cJson

Previously, we retrieved the sequence no. from presence payload
using object->valueint. Since the sequence no. is 32-bit unsigned
int, this caused the valueint to overflow. Hence, changing it to
object->valuedouble. This should fix IOT-549.

Change-Id: Idd30408c617e2ff84faa7c7c7f2a3f028577d337
Signed-off-by: Omkar Hegde <omkar.m.hegde@intel.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/1245
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Erich Keane <erich.keane@intel.com>