Added win/loss mechanism and return to lobby

The matches now end and players are told the result, and the game can
then return to lobby.

I haven't added an actual image to tell the players that they won or
lost, i've only added the final mechanism to indicate victory or defeat.
receiving input screen draws over previous screen

When the screen goes to the receive input screen the previous window is
copied that way the receive window message is drawn over the previous
window.