overflow for 'DejaVu Sans'.

This renames the local_client zone to loc_client, as local_clint exceeds
the maximum zone length allowed for firewall3, which is 11 bytes.

This worked previously due to firewall3 using unsafe string operations.
Now creation of the chain fails (latest OpenWrt master).

This adds the wireless client count for 2.4GHz and 5 GHz radios to the
status page. Previously, only the total client count advertised by
the mesh protocol was visible.

This reverts commits
- caf2dd03.
- 07ebac6a
- 55eff45f

I accidentally pushed these commits as I had them lying around on a
dirty checkout I did testing on.

The original commit only applied its changes to the source file and did
not rebuild the minified file, therefore the change never went live.

Fixes: #659
Signed-off-by: Martin Weinelt <martin@darmstadt.freifunk.net>

Let gluon-respondd expose "MemAvailable" from /proc/meminfo to allow for
a more realistic memory-usage estimation.

Information on MemAvailable can be found here:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
commit/?id=34e431b0ae398fc54ea69ff85ec700722c9da773

The field was accidentally removed during the status-page rewrite.

Fixes #1401

batman-adv-specific parts are moved to a new package
gluon-status-page-mesh-batman-adv.

gluon-status-page: reduce usage of absolute paths in cgi-bin scripts neighbours-nodeinfo and stations

The field is unused.

Some HTTP endpoints were writing annoying "broken pipe" messages to stderr.

A downside of this behaviour is that the page does not work for IPv4-only
clients, as the redirect will always point at an IPv6 address.

Still, it seems like a good idea to enforce the redirect even from the IPv4
next-node address, as switching nodes while being connected to the status
page would lead to unexpected behaviour.

All Access-Control-Allow-Origin are removed to improve users' privacy. As
the status page API is thus not useful without the status page anymore,
merge them back into a single package.

The status-page-api respondd provider is removed as well.

Fixes #1194

This new status page is significantly smaller than the old one. It always
loads its resources from the same host as the page itself, not requiring
cross-origin requests anymore.

It also uses the common i18n infrastructure of gluon-web.

Fixes #914