Prompt for tor controller password if needed

We use getpass for this (i.e. text mode).
This means that if you have password protection for your
Tor controller (advised) and you want to run onionshare-gui,
you need to do it from a terminal (so that you can enter
the password).
i18n for "Tor control password" prompt
Add option for persistent hidden service

(needed for HiddenID). Can't be set from command line.
Fix CLI to exit when server is shutdown

Conflicts:
	onionshare/onionshare.py
Merge branch 'hidden-id' of github.com:hidden-id/onionshare into hidden-id

Conflicts:
	onionshare/onionshare.py