Warn of empty msgstr in translations, hint at using comments

When rebooting the node in config mode, currently the fastd key is
forcefully displayed in a fixed format. This is confusing in communities
where fastd accepts all keys and no key submission is needed.
Furthermore, some communities might want to personalize the display of
the key (see #387).

This patch moves the displaying <div> from the package's lua file to the
translation files of the sample site configuration and mentiones the
change in the release notes.

Apart from replacing a patch for the former by two patches for latter,
this involved minimal adaptations of the lua scripts in the following
packages:

* gluon-announce
* gluon-announced
* gluon-mesh-batman-adv-core
* gluon-status-page

Split basic radio configuration from gluon-mesh-batman-adv as this will
be required for virtually any wireless mesh protocol.

This package takes care of setting:

  - wireless channel,
  - htmode and
  - regulatory domain

gluon-mesh-batman-adv-core depends on this package.

Documentation for packages should be placed in docs/packages/
and be added to docs/index.rst.

This broke due to a recent OpenWrt update.

Fixes site.conf checks.

This also updates batman-adv & alfred to 2015.1

This should workaround batman-adv's inability to deal with different MTUs
which need fragmentation.

Fixes #435

This might improve stability on the TL-WR841 v9.

Add support for TP-Link TL-WR710N v2

Tested-by: @kokel

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,
            },
    },

Using service_start requires exporting of environment variables.

Fixes #397

The nodeinfo/network/addresses announcement included deprecated and
tentative addresses, which it clearly shouldn't as the host doesn't want
to be contacted on those addresses. They are now filtered out.

TP-Link TL-WA701ND v2: remove BROKEN

hostapd would switch the primary and secondary channel on 5GHz networks in
certain circumstances, completely breaking the adhoc interfaces of the WLAN
adapter (they would lose their configuration).

As a temporary fix, disable this channel switch function.