* Added trigger for form valid and invalid.
* Added on valid and invalid for form field.
* Added settings for add error class to form field on invalid.
* Added more ways to set the label for error message.
* Changed the way required work.
* Change the way min work.
* Added required_if rule that checks if a field has a value and the expect a value in current field.
* Added no_html rule that checks if field contains html.
* Added image rule that checks if field contains an image name.
* Solved problem with if last rule was valid, the field was valid even if a rule was invalid.
* Added plugin functions for form and single field.