XXX Import Tor Launcher @ commit 1d5d571.
Add a dedicated user for the tor-launcher.
Add start script for tor-launcher.
Add shell library functions for modifying torrc.
Give tor-launcher access to Tor's control port.
Start Tor Launcher when in bridge mode.
Remove workaround when in bridge mode.

This workaround was only relevant with our previous, hackish,
experimental bridge mode implementation.
Cleanup after exit to save some RAM.
Don't ever run Vidalia with -bridgeconf.

We know handle the initial bridge configuration in Tor Launcher.
Drop unused variable.
Rework how we (re)start vidalia.

The old behaviour of restart-vidalia sometimes causes a number of
issues:

* Vidalia fiddles with the signal handler for SIGINT and SIGTERM,
  delaying termination for up to several seconds when vidalia has just
  started (before its systray icon goes "green"). In that case
  restart-vidalia will fail to kill vidalia in time to start it via
  lckdo, so it just fails. The old vidalia process finally dies
  sometimes after that failure, leaving the user with no vidalia.

* If vidalia is running (e.g. after the first network connection has
  completed) then restart-vidalia is called from restart-tor, which in
  turn is called from the 10-tor.sh NM hook. restart-vidalia is
  blocking, so in this situation all execution is blocked until the
  vidalia process is killed, which probably won't happen until the
  *next* network connection. The results of this is that all NM hook
  code after restart-tor is called in 10-tor.sh during a second
  network connection is delayed until the third network conncetion,
  and the third's to the fourth, and so on.

We fix this by simply SIGKILL:ing vidalia and making sure it's always
started in the background (non-blocking). In this context, lckdo isn't
very relevant may just as well drop it.
Fixup sudoers for tor-launcher.

root obviously doesn't need an entry, and the live user only need to
run it with --force-net-config.
Use settings from TG for netconf/bridge-mode.
Factorise shell library.
Remove tcp white-listing for the DNS port.

Tor's DNSPort only listens with UDP.
Move Tor's DNSPort to 5353 and redirect system DNS to it.

When we set DisableNetwork most of Tor's listeners are delayed to
after it has setuid:ed away from root (to debian-tor) which causes
errors if it tries to listen on ports <1024.
Set obfsproxy path in Tor Launcher's default prefs.
Merge branch 'devel' into feature/bridge-mode
Add documentation for Network configuration startup option
Update the startup options index