move style icon into Lua

stepmania/Themes/default/Graphics/ScreenWithMenuElements StyleIcon/default.lua

@@ -0,0 +1,11 @@
+local style = GAMESTATE:GetCurrentStyle();
+if not style then return Def.Actor {}; end
+
+local s = style:GetName();
+local Reverse = PlayerNumber:Reverse();
+
+local t = LoadActor("_icon " .. s)() ..  {
+	InitCommand = cmd(pause;setstate,Reverse[GAMESTATE:GetMasterPlayerNumber()]);
+};
+
+return t;