Add isOnHold() method, which tests if the sub-section of SDP has a request to put session on-hold. We test for all 3 methods (old way to put 0.0.0.0, new way via sendonly and inactive attributes).
Add isOnHold() method, which tests if the sub-section of SDP has
a request to put session on-hold. We test for all 3 methods
(old way to put 0.0.0.0, new way via sendonly and inactive attributes).

sippy/rtp_cluster,sippy/rtp_cluster