fix preset failing to default

config.lua

@@ -1,4 +1,4 @@
-preset = rawget(_G, 'preset') or 'ars'
+local preset = rawget(_G, 'preset') or 'ars'
 
 local common_cfg = {
     -- read-only modes:

main.lua

@@ -2,7 +2,7 @@ local globalize = require("strict")
 
 -- configuration.
 
-globalize{preset = arg}
+globalize{preset = rawget(_G, arg)}
 local cfg = require("config")
 local gcfg = require("gameconfig")