Update License
Update gemspec, bump required Ruby
Use Vagrant master from GitHub
Fix Travis
Add a better gitignore
Update license year
Remove integration folder and files (not used)
Rewrite vagrant-berkshelf to follow Vagrant plugin best practices

This is a breaking commit for many internal APIs. It does not change the
public API. It changes the namespace for the gem, adds more test
coverage for different options, and fixes a number of bugs around
multi-machine Vagrantfiles.
Fix up README