The what's new document is updated in separate step.
Explain when to add a 'Next Release' heading.
Add Phantomjs to your path on linux
Split the key add and acceptance running into separate steps
Merge pull request #1019 from ClusterHQ/better-release-docs-FLOC-1072

[FLOC-1072] Some improvements to the release docs following the aborted 0.3.3dev1 release.