Add confirm pass in GOSU.

[E_Slumb]

i know it's already alright the way it is now. But i'd appreciate a confirmation to pass, most especially if the player still has one/two activation tokens laying around.. It's a no-brainer that a player would want to use the tokens before passes, and players sometimes overlooked em tokens.

Also, at times a player may double-clicked the pass button and consequentially locked out of the next round.. Like what happened to me in this game: Gosu n°9493471 (move 50 and 51).