set window objects to global

Reviewed-on: http://git.teletype.hu/games/impostor/pulls/10

.luacheckrc

@@ -14,6 +14,16 @@ globals = {
   "Context",
   "Meters",
   "Minigames",
+  "SplashWindow",
+  "IntroWindow",
+  "MenuWindow",
+  "GameWindow",
+  "PopupWindow",
+  "ConfigurationWindow",
+  "AudioTestWindow",
+  "MinigameButtonMashWindow",
+  "MinigameRhythmWindow",
+  "MinigameDDRWindow",
   "mset",
   "mget",
   "btnp",

inc/init/init.modules.lua

@@ -1,13 +1,13 @@
-local SplashWindow = {}
+SplashWindow = {}
-local IntroWindow = {}
+IntroWindow = {}
-local MenuWindow = {}
+MenuWindow = {}
-local GameWindow = {}
+GameWindow = {}
-local PopupWindow = {}
+PopupWindow = {}
-local ConfigurationWindow = {}
+ConfigurationWindow = {}
-local AudioTestWindow = {}
+AudioTestWindow = {}
-local MinigameButtonMashWindow = {}
+MinigameButtonMashWindow = {}
-local MinigameRhythmWindow = {}
+MinigameRhythmWindow = {}
-local MinigameDDRWindow = {}
+MinigameDDRWindow = {}
 Util = {}
 Meters = {}
 Minigames = {}