Allow players to manually start a game in duels

Before you start a duel you should be allowed to accept game after an opponent have been found. The main reason for this is that it solves the problem where the lobby sometimes take a lot of time to find an opponent, only to find one just when you exit the lobby because of the wait time (this has happened to me multiple times and probably cost me several hundred rating points in total). It can also allow you to avoid playing the same opponent multiple times in a row, which often happens when you reenter the queue right away after a game and can be annoying when you want to play someone new. On top of that it would solve the problem that the matchmaking sometimes pairs you against people with completely different ratings from your (being around 900-1000, I've been paired against both 400 rated players and 1200+ rated players, making the result almost predetermined). It could perhaps work to just abort the game without changing your rating if you left the lobby before the first round begins. Or you could have around 10 seconds to click a "begin"-button before it automatically aborts, perhaps similar to how most chess websites only start the game after the first move has been made.