TOOLS: autoload.lua: sort files case insensitive

Suggested by a user. The suggested code which was added her comes from
PIL.

TOOLS/lua/autoload.lua

@@ -28,7 +28,9 @@ function find_and_add_entries()
     if files == nil then
         return
     end
-    table.sort(files)
+    table.sort(files, function (a, b)
+        return string.lower(a) < string.lower(b)
+    end)
     if dir == "." then
         dir = ""
     end