handle AutoStyle bug (sort of)

This commit does two things:

1. It causes screen branching to ignore AutoStyle when CoinMode is Pay. If CoinMode is Pay, players should always be directed to ScreenSelectStyle to manually choose a style.

This makes sense in the context of a public arcade (that might have accidentally set the AutoStyle setting) while still allowing the setting to exist for private machine owners and keyboard players.

2. If AutoStyle is set to 1 Player, and CoinMode isn't Pay, and both players have already been joined on ScreenTitleJoin, forcibly unjoin PLAYER_2 to prevent possible theme errors like "too many players joined for single" or "no style set" and etc.

Hardcoding the theme to unjoin PLAYER_2 isn't a great fix, but I'm not sure how else to handle the problem at this time.

Scripts/SL-Branches.lua

@@ -53,12 +53,25 @@ end
 
 Branch.AfterScreenSelectColor = function()
 	local preferred_style = ThemePrefs.Get("AutoStyle")
-	if preferred_style ~= "none" then
+
+	if preferred_style ~= "none"
+	-- AutoStyle should not be possible in pay mode
+	-- it's too confusing for machine operators, novice players, and developers alike
+	and GAMESTATE:GetCoinMode() ~= "CoinMode_Pay" then
+
 		-- If "versus" ensure that both players are actually considered joined.
 		if preferred_style == "versus" then
 			GAMESTATE:JoinPlayer(PLAYER_1)
 			GAMESTATE:JoinPlayer(PLAYER_2)
+
+		-- if "single" but both players are already joined (for whatever reason),
+		-- we're in a bit of a pickle, as there is no way to read the player's mind
+		-- and know which side they really want to play on
+		-- Unjoin PLAYER_2 for lack of a better solution
+		elseif preferred_style == "single" then
+			GAMESTATE:UnjoinPlayer(PLAYER_2)
 		end
+
 		GAMESTATE:SetCurrentStyle( preferred_style )
 		-- set this here to be used later with the continue system
 		SL.Global.Gamestate.Style = preferred_style