OpenVPN GUI Service pack #1

SP contains the following changes to OpenVPN GUI:
1. Fix for #3401 (Added an option for "tun": "Disable IPv6");
2. New GUI options on Client and Server pages:
    - Don't pull routes (route-nopull)
    - Don't add/remove routes (route-noexec)
    - Verbosity level (verb)
You can just back "dev " as the first set of $conf, since dev is mandatory, and change verb to a .= sentence, when necessary.