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

`make show-release` can be used to discover the current release in scripts.

A bug in batman-adv can lead to a large amount of management traffic being
exchanged between nodes when the multicast optimizations are enabled,
effectively making the mesh unusable. It's safer to disable the feature
for now, until we have a real fix.

sha512sum doesn't add much code that is not also used by sha256sum, but the
change of the configuration hides the segfault issue described in:

  https://bugs.lede-project.org/index.php?do=details&task_id=822

While the issue only seemed to affect dhcpv6.script, it would clutter /tmp
with coredumps, eventually leading to OOM.

This patch got lost in the OpenWrt -> LEDE transition and fixes flash
writes on new UBNT PicoStations.

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 used nodejs 4.4.5 needs at least GCC 4.8 to be build
https://github.com/nodejs/node/blob/v4.x/BUILDING.md



Signed-off-by: Matthias Fritzsche <matthias@chemnitz.freifunk.net>
[Matthias Schiffer: moved information to the first section]

Allow the autoupdater to work when updating from the removed targets.

iptables will be pulled in anyways.

These devices have never actually existed; the corresponding support
strings have been removed from the stock firmwares as well.

It seems the device was lost during the OpenWrt -> LEDE migration.

This reverts commit fcce9e52.

The x86-generic kernel does not fit into 4MB.

Backport another sysupgrade patch.

Fixes #1130

Updates batman-adv and alfred to 2017.1. This also allows us to drop our
last batman-adv patch.