Subscriptions and Notifications for Endpoint Registry and Policy Repository

Adding subscription and notification for Endpoints and Policies. Added the
Policy Unresolve message, allowing agents to unsubscribe to policies. Also
fixed excessive whitespace.

Change-Id: I7ef120071bc19acac006c34943adc6b440e7f7f7
Signed-off-by: Thomas Bachman <tbachman@yahoo.com>