The new routing_algo site.conf value BATMAN_IV_LEGACY is introduced. With
these changes, the routing_algo setting becomes mandatory.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>

The batctl v2013.4 build was removed from the batman-adv-legacy package
as the current, upstream batctl releases work with batman-adv-legacy,
too.

As a replacement we need to add the upstream batctl dependency to
gluon-mesh-batman-adv-14 to have a batctl available again here.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>

Signed-off-by: Sven Eckelmann <sven@narfation.org>

For simplicity, we don't use different MTUs for compat 14 and 15 anymore,
there's no harm in using 1532 for batman-adv-legacy as well.

gluon-mesh-batman-adv should not be used without firewall to prevent forwarding
of packets from the mesh to the wan interface.

For some reason, the firewall package won't work at all without
kmod-ipt-nathelper.