Merge pull request #126 from petergoldstein/feature/travis_update

Travis Update
Let's try Rubinius again.
Add experimental syntax suggested in issue #104.
2.1.0, describe experimental syntax.
Add def clean doc. Add Belarus example.
2.1.1, Fix for case where country code is already in number when normalizing a specific country.
Fix Belgian numbers (closes #130).
Add reference for Belgium.
Change to RSpec expect syntax.  Replace 'be_true' and 'be_false' matchers with 'be true' and 'be false'.