Sketch of adding environment variables for controlling links.
Implementation.
Merge branch 'config-internal-links-201' into links-environment-variables-91.
Add links to Application in test_deploy.
Add hostname to StartApplication in tests.
lint
_link_environment should be a free function.
Document this.
Merge remote-tracking branch 'origin' into links-environment-variables-91

Conflicts:
	flocker/node/_config.py
Fix gear environment.
Test for fixed gear env.
lint
Add a functional test for links too.
lint
Use an infinite loop, rather than sleep.
Typos.
Fix environment variable names to match docker.
Add package_data.
Review comments.
What's new.