The next-node MAC address doesn't need to be unique in different
communities, so we can as well add a default value.

The SSID for the mesh network should be cryptic, otherwise some users will try to connect to that network and have a bad user experience.

The fastd_mesh_vpn site.conf section is renamed to mesh_vpn.fastd.

and add documentation

I guess this is some copy and paste mistake which makes the example an
invalid site.conf. In my case merging the changes of the example into
our actual site.conf lead to an error because this line was merged to.

Fixes #487

The Gluon-specific functions of the gluon-simple-tc package are moved to
gluon-mesh-vpn-fastd.

Fixes #401

This is a site.conf-breaking change in regard to the wireless config.
Make sure to read http://gluon.readthedocs.org/en/latest/user/site.html
and update your site.conf accordingly!

Support for 802.11s mesh interfaces has been added. Gluon now supports
three interface types: ap, ibss and mesh. All of them are now optional
and may be configured independently in site.conf.

A sample site.conf may look like this:

    wifi24 = {
            channel = 1,
            htmode = 'HT40+',
            ap = {
                    ssid = 'luebeck.freifunk.net',
            },
            ibss = {
                    ssid = '02:d1:11:37:fc:38',
                    bssid = '02:d1:11:37:fc:38',
                    mcast_rate = 12000,
            },
            mesh = {
                    id = 'ffhl-mesh',
                    mcast_rate = 12000,
            },
    },

This PR documents functionality added by
https://github.com/freifunk-gluon/packages/pull/95

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

 - generalize, to make it more clear that the site config
   needs to be adapted to the local community.
 - remove some host names and public keys used in Lübeck
 - suggest private space mac adresses
 - change fastd method to salsa2012+umac, which is the recommended default
 - add config for a fastd peer reachable by both ipv4 and ipv6
 - order GLUON_SITE_PACKAGES alphabetically

Link to timezone configuration help had a wrong anchor