Make Pay mode work like Free

Third time's a charm.  Removing Pay mode without causing breakage to the Lua API.
This is the first step.

src/ScreenWithMenuElements.cpp

@@ -134,14 +134,6 @@ void ScreenWithMenuElements::BeginScreen()
 
 	/* Evaluate FirstUpdateCommand. */
 	this->PlayCommand( "FirstUpdate" );
-
-	/* If AutoJoin and a player is already joined, then try to join a player.  (If no players
-	 * are joined, they'll join on the first JoinInput.) */
-	if( GAMESTATE->GetCoinMode() == CoinMode_Pay && GAMESTATE->m_bAutoJoin.Get() )
-	{
-		if( GAMESTATE->GetNumSidesJoined() > 0 && GAMESTATE->JoinPlayers() )
-			SCREENMAN->PlayStartSound();
-	}
 }
 
 void ScreenWithMenuElements::HandleScreenMessage( const ScreenMessage SM )