3rd party frameworks or plugins may like to extend the 'syscalls', come up 
with an inerface for this

the current cmd interface uses isinstance to difrentatie between commands, this
is fairly easy to extend to arbitrary cmds and handler methods, an api for 
registration and calling the implementation need to be toughtout about and 
implemented

Caveats:
there are some stylisitic issues here and soem performance ones, this code 
needs to be eyeballed by others before being merged

Ideas:
Implement the registry as a dict and provide a decorator for implemetnation, 
reuse the entry system used in config/cli to indicate loadable moduels entry 
points (and hoist module loading to the server in a standardised way rather 
than user code import) and then implement the dispatch as iteration of the dict 
with sucsessive `isinstance` calls
