Use lightGrey for folders on normal computers

This way we still get some differences between files and folders on
normal computers. I did try with just green, but I think the contrast is
too low.

Closes #656

src/main/resources/data/computercraft/lua/rom/programs/list.lua

@@ -33,5 +33,5 @@ table.sort(tFiles)
 if term.isColour() then
     textutils.pagedTabulate(colors.green, tDirs, colors.white, tFiles)
 else
-    textutils.pagedTabulate(tDirs, tFiles)
+    textutils.pagedTabulate(colors.lightGray, tDirs, colors.white, tFiles)
 end