Plus a bunch of changes which were necessary for the script to work:
* The "simulate lobby activity" plugin now exits when the server is shut
down.
* The plugin now uses wesnoth.random() for random number generation.
Math.random() uses a fixed seed, which would make all the clients
perform the exact same actions.
* Exposed wesnoth.random() to plugins to allow the change above.
* --nogui no longer implies --wconsole on Windows. With implied --wconsole
the clients attached themselves to the standard output of the Python
script, which made it impossible to see the output of the script itself.
