Merge tag 'upstream/1.18.0+dfsg1' into debian/experimental

Upstream version 1.18.0+dfsg1

# gpg: Signature made Wed 21 Jun 2017 00:28:07 CEST
# gpg:                using RSA key 3667486A326DB2766D255546860DEF3B8F650B79
# gpg: Good signature from "Ximin Luo <infinity0@pwned.gg>" [ultimate]
# gpg:                 aka "Ximin Luo <infinity0@torproject.org>" [ultimate]
# gpg:                 aka "Ximin Luo <infinity0@freenetproject.org>" [ultimate]
# gpg:                 aka "Ximin Luo <infinity0@debian.org>" [ultimate]
# gpg:                 aka "Satoshi Nakamoto (www.bitcoin.org) <satoshin@gmx.com>" [ultimate]