First half of "hello, world" extension actions - displays link

Split out module name determination into actions._getmod() function
Much more complete function/method/class docstrings
Normalize tooltip whitespace
Second half of "hello, world" extension actions - displays output
Hello world fixes

Use title, rather than id, to identify instances in link (less fragile to reloads)
Put output in a <p>
Un-stub the showoutput function