Important Changes:
As mentioned here #10 The required rule was misleading in the previous releases, it implied that the fields that are not required should pass the validation if they had empty values and that is indeed the intended behavior. However that wasn't the case, some fields passed, some didn't depending on how each validates empty values.
This release fixes that behavior. From now on, all fields that do not have the required rule will pass the validation if they have empty values. Those empty values are: null, undefined and ''. if a non-empty value was provided it will proceed to validate them as before.