gluon-autoupdater: Always allow forced autoupdate.

On nodes with autoupdate disabled the cmdline parameter '-f' has no
effect. But using the autoupdater for manual updates is quite handy.
Merge pull request #23 from sargon/autoupdate-enforce

gluon-autoupdater: Always allow forced autoupdate.
gluon-mesh-batman-adv: Do not ACCEPT incoming packets.

For security reasons we should not accept incoming packets per default
and instead allow specific services on specific interfaces.
gluon-firewall: Accept common services.

Allow ssh on client and wan, additional allow http,dns and icmpv6
on client network. Also ensure that the client and wan interfaces reject
incoming connections as default.