Document endpoint states, check transistions more rigorously

Change-Id: I0d86d91a91c67e54fd41d3446050f00ccb0c49c5
Signed-off-by: Craig Dowell <cdowell@qce.qualcomm.com>
Remove half-baked code accidentally left in

Change-Id: Ie8da20d3a2bd36a74d55ed7f634e3e2c7d9ba55c
Signed-off-by: Craig Dowell <cdowell@qce.qualcomm.com>
Merge changes Ie8da20d3,I0d86d91a into feature/udp_transport

* changes:
  Remove half-baked code accidentally left in
  Document endpoint states, check transistions more rigorously