replaysync support

You need the replaysync tool to get it work. (http://dropcanvas.com/tgnyf)

If the game started with /syncreplay and /gpgnet parameters:
* it will send the players current ticknumber on every beat to the lobby program.
* adds option to pause the game from the lobby program
* adds option to change speed from the lobby program
* displays a helper dialog while downloading replay from the lobby program