Fix Cask URL and archive name

Cask was moved into its own organisation, and consequently URLs and
package name has changed.
Improve nodejs module and provisioning

The latest nodejs Puppet module properly installs Nodejs on Ubuntu
12.04, hence we can get rid of our manual approach.
Fix test regression from 4d32595
Fix test regression from 671ea85
Remove superfluous broken tests
Fix checkdoc predicate
Do not test js3

See thomblake/js3-mode#89