Proxy: Use trust-dns-resolver for DNS.

trust-dns-resolver is a more complete implementation. In particular,
it supports CNAMES correctly, which is needed for PR #764. It also
supports /etc/hosts, which will help with issue #62.

Use the 0.8.2 pre-release since it hasn't been released yet. It was
created at our request.

Signed-off-by: Brian Smith <brian@briansmith.org>

Author: briansmith