Add parent to interests in protocol docs.

Existing protocol messages would now also send ENTER_OBJECT for the parent object.
Add a new protocol message to explicitly subscribe to an object but none of its zones.
ClientAgent: Implement CLIENTAGENT_GET_REMOTE_ADDRESS. Closes #303
Docs: Document CLIENTAGENT_GET_REMOTE_ADDRESS
ClientAgent: Change CLIENTAGENT_GET_REMOTE_ADDRESS msgtype
Docs: Add missing arg
ClientAgent: Change CLIENTAGENT_GET_REMOTE_ADDRESS msgtype again
Tests: Add test for CLIENTAGENT_GET_REMOTE_ADDRESS
ClientAgent: Extend CLIENTAGENT_GET_REMOTE_ADDRESS to return remote port, local ip and local port
Docs: Improve wording
Merge branch 'master' of https://github.com/loblao/Astron into loblao-master
Merge branch 'loblao-master' into develop
Merge pull request #304 from loblao/master

ClientAgent: Implement CLIENTAGENT_GET_REMOTE_ADDRESS. Closes #303