Add an admin shell/console for interactive debugging of live server

[nsjph]

An integrated shell, similar to supervisorctl or a router console would be a useful interface for interacting with a running server, inspecting the state of connections and the network, and modifying the live configuration.

Initial thoughts are to embed something like glisp to create a scriptable interface, and expose functions and internal state to the glisp virtual machine. This would be designed for administrative/development use only, and restricted accordingly.