Plumbing for iCalendar Period and Recurrence

Plumbing for iCalendar Period and Recurrence

Added the iotvticalendar.h file
Added function and unittest to parse period
Added function and unittest to parse recurrence rule
Added function and unittest to check if access is within
allowable period

Change-Id: Ic1236b96b9c786f3c74c61ddfcb7ab56c27bc320
Signed-off-by: Shilpa Sodani <shilpa.a.sodani@intel.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/1434
Reviewed-by: Sachin Agrawal <sachin.agrawal@intel.com>
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>