Fix various 20141120 (for PortForwardManager)

This is currently for review only, and for sharing with @Nakomis
I'm happy with the first two commits; but not the "TODO Hack" commit!
Adding javadoc:

    /**
     * The intention is that there is one PortForwardManager instance per "scope". If you 
     * use global, then it will be a shared instance (for that management context). If you 
     * pass in your own name (e.g. "docker-fjie3") then it will shared with just any other
     * places that use that same location spec (e.g. {@code portForwardManager(scope=docker-fjie3)}).
     */