Refactor
Add spanish language
New *breaking* behaviour: A null or empty input will pass validation unless the required rule is specified
New validation rule `blank`
PSR-2 compliance
Refactoring
Update tests for new non-required behaviour
Add more tests
Add tests for new rule: blank
Add tests for missing rules: numeric, float, alpha_numeric, max_length, min_length, exact_length
Refactoring