Improve network performance for VirtualBox

Without those lines, VitrualBox machines are being very slow with all network operations (tested only in OS X Lion, but they are supposed to work everywhere). See https://github.com/mitchellh/vagrant/issues/1807
abord build if mergeConfig returns an error and fix duplicate error message
Merge pull request #2034 from metalivedev/1969-cherrypick-fixcommitformat

Fix #1969 formatting, add information about multiline json
Add test
add missing error check
added initial draft of the Docker infrastructure doc
Minor updates to postgresql_service.rst

I've added the steps that were missing/wrong for me when I went through this just now.
tell the new developer how they can replace the real docker binary with the one they've been hacking on (#2142)
testing, issue #1766: Add nightly release to docker-ci
testing, issue #1766: Upgrade tooling for Docker nightly release
testing infrastructure, issue #1766: Temporarily install docker with proper apparmor handling
testing infrastructure, issue #1766: Dockerize deployment of docker-ci
Merge pull request #1813 from doubleyou/patch-1

Improve network performance for VirtualBox
Merge pull request #1823 from dotcloud/1766-nightly-release

testing, issue #1766: Add nightly release to docker-ci
Merge pull request #2142 from SvenDowideit/patch-1

tell the new developer how they can replace the real docker binary with ...
Merge pull request #2160 from iffy/patch-1

Minor updates to postgresql_service.rst
Prevent docker-ci to test closing PRs
Merge pull request #2211 from mzdaniel/2190-docker-ci

Prevent docker-ci to test closing PRs
Remove @KSid from contrib maintainers for now

His availability has been very limited, so I'll take over completely for the short term until he can find more time to help out.
Merge pull request #2218 from tianon/ksid

Remove @KSid from contrib maintainers for now