Extract sanitizer plugin into its own repo
Merge pull request #104 from guardian/sc-extract-sanitizer-plugin

Extract sanitizer plugin into its own repo
Looser version for plugins

[ci skip]
Tidy up

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Allow tests to be run in Sauce Labs using `RUN_IN_SAUCE_LABS`
Do not encrypt Sauce Labs username/access key

This allows tests to run from foreign PRs, re. http://docs.travis-ci.com/user/pull-requests/\#Security-Restrictions-when-testing-Pull-Requests
Add docs on how to run tests in Sauce Labs

[ci skip]