validaForms: Validate web forms using localized error messages

This class is meant to validate the input values of Web forms.

It supports several types of input validation returning localized error messages according to the idiom that was chosen. The localized text is defined in separate files for each of the supported idioms. Currently, the error messages are available in English, Portuguese, Italian and German.

Currently it supports the following validation types:

- Numeric, alphanumeric, letters only, required, minimum and maximum length
- Date
- E-mail
- Password
- Checkbox
- Dropdown select field
- Radio button field

The class also has some interesting features like associating a text input with a select input. It is useful when you must receive an input text set to an alternative value besides those available in the select input that has a special value for specifying "other" using the text field.

A similar feature is available for radio fields that may be associated with a text field that has to be set by the user when the radio button is checked.