* Remove __call in favor of more explicit `rule` method - smaller API
to maintain without magic method use
* Updated README with current supported rules
* Initial English error messages file and directory
* Setup methods to specify language and directory to find lang files in
* Change 'alphaDash' validation name to 'slug' for URL slugs
* Now passing all parameters to error message via `vsprintf`
* Add `message` convenience method to easily specify custom message on
last validation rule
* Add tests for error messages