Add "Assume prefered languages per LANG" setting for firefox.

Now Twitter and Nico-nico etc. show Japanese pages by default.

Author: tsutsui

liveimagefiles/firefox/defaults/pref/local-prefs.js

@@ -1,6 +1,9 @@
 // choose useragent locale per LANG
 pref("intl.locale.requested", "");
 
+// Assume prefered languages to show pages per LANG
+pref("intl_accept_languages", "");
+
 // Enalbe Network Manager integration
 pref("network.manage-offline-status", true);