Update README for consistency with other modules

Remove duplicate info from manifest
Update LICENSE for 2014
Simplify type and value checks

Use validate_re() instead of checking type and use case statements to
validate code. This greatly simplies things.
Style fix for spec tests.

No changes to testing with this commit. Style changes only.
Refactor spec tests for simplicity
Support Ruby v2.0.0
Merge pull request #14 from ghoneycutt/modernize

Modernize