Error message support

[tasomaniac]

The library has various validation methods but we cannot give any error message to the user.

For example if a field has a maximum value of 500 and it the user gives 600. It gives error indicator but does not give any feedback to user. I think it needs integrated message system that displays the error message below the views.

[jessedc]

EZForm has deliberately stayed away from getting too involved with your user interface, but off the top of my head I can think of a few extensions to the validation functionality that might bet useful.

Features are added to EZForm as they're needed, feel free to submit a PR with some suggestions ;)