fixes #1561

Fixes: #1463

dnsmasq's caching is severly broken and does not handle all answer records
equally. In particular, its cached answers are missing DNSKEY and DS
records, breaking DNSSEC validation on clients.

Remove the cache for now. It may return if dnsmasq is fixed or we switch to
a different resolver.

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]