Drop beaker acceptance tests.

We don't use beaker just yet.
Stop ignoring the modulesync.yml file.
Update for razorsedge.
More razorsedge-specific changes.

Remove moduleroot/CONTRIBUTING.md.
Update ignore/exclude paths in moduleroot/Rakefile.
Support allow_failures in .travis.yml.
Use Travis features cache and contrainers.
Set puppetlint fail_on_warnings=true.

Otherwise it does not work.