fix broken GUI library

Barotrauma/BarotraumaClient/ClientSource/Lua/LuaClasses.cs

@@ -14,7 +14,10 @@ namespace Barotrauma
 			public LuaGUI(LuaSetup _env)
 			{
 				env = _env;
+			}
 
+			public void CreateStaticValues()
+			{
 				RectTransform = UserData.CreateStatic<RectTransform>();
 				LayoutGroup = UserData.CreateStatic<GUILayoutGroup>();
 				Button = UserData.CreateStatic<GUIButton>();
@@ -33,7 +36,6 @@ namespace Barotrauma
 				Anchor = UserData.CreateStatic<Anchor>();
 				Alignment = UserData.CreateStatic<Alignment>();
 				Pivot = UserData.CreateStatic<Pivot>();
-
 			}
 
 			public ChatBox ChatBox

Barotrauma/BarotraumaShared/Lua/DefaultLib.lua

@@ -101,6 +101,8 @@ elseif CLIENT then
 	defaultLib["Sprite"] = CreateStatic("Sprite")
 	defaultLib["Keys"] = LuaUserData.CreateStatic("Microsoft.Xna.Framework.Input.Keys")
 	defaultLib["PlayerInput"] = CreateStatic("PlayerInput")
+
+	GUI.CreateStaticValues()
 end
 
 return defaultLib