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]

Add missing trailing `,` in simple_tc section and change the order of ingress and egress to default format used by Gluon.

docs: add D-Link DIR-505 (A1) and Buffalo WZR-HP-G300NH (and remove WZR-HP-G300N, it is not actually supported)

Also
* create list of newly supported devices since v2015.1.2 in the v2015.2 release notes
* update information on docs/user/x86
* fix a comment in targets/ar71xx-generic/profiles.mk