I just followed this document on a Debian Stretch, and it worked out of
the box. So let's use Debian's current stable release here.

Signed-off-by: Christoph Krapp <achterin@googlemail.com>

Signed-off-by: Martin Weinelt <martin@darmstadt.freifunk.net>

fixes #1561

Before 7827f896, mandatory hostname field in config mode was
pre-filled with the default hostname.

This commit adds the config_mode.hostname.prefill option for
controlling the default value.

gluon-config-mode-geo-location-osm extends the
gluon-config-mode-geo-location with a location picker based on
OpenStreetMaps.

Based-on-patch-by: Jan-Tarek Butt <tarek@ring0.de>

As already done with other config mode texts, the altitude field now has
default texts that are used when they are not set in the site i18n files.
The altitude-help text has been removed from site i18n; instead, the
geo-location-help text now overrides the whole section description
including the part that mentions the altitude.

Fixes #1491

Addition of the OCEDO Koala to the supported devices in the docs was
forgotten in 52bc028e.

This device is a dual 5GHz device. It is recommended to manually change the
radio of the first device to the lower 5GHz channels and the second radio
to the upper 5GHz channels.