Added support for OpFlex Endpoint Registry messages.

This adds support for Endpoint Declaration and Endpoint Request
messages. It converts between OpFlex semantics to the semantics
needed by the Endpoint Registry.

Change-Id: Ic9c869e549ad3f70a5089ad2c9218754726aa1f4
Signed-off-by: Thomas Bachman <tbachman@yahoo.com>
Merge "Added support for OpFlex Endpoint Registry messages."