removed dependency on wget
removed useless config line

(X11 forwarding is enabled by default
 and /etc/ssh/ssh_config is not the server config file)
replaced ENTRYPOINT with CMD

CMD is more adequate here (there is no need to append extra
arguments to the sshd command at runtime)
added a makefile and launch script

The only config required from the user is to allow network
connections in the pulseaudio daemon, then a « make run »
will do the rest.

The scripts handle all the setup and cleanup stuff, especially :
- generate a temporary ssh key to log in the container
- copy the pulse-audio cookie (disabling authentication is no
  longer required)
- start the container and stop/remove it once skype exits
- catch SIGINT/SIGTERM so that container is cleaned up in any case
do the pulseaudio config with the gconftool directly

Thus installing paprefs is no longer needed
added warning in the FAQ