ValidatorClass: Validation of data submitted via Web forms

This is a simple class meant to validate data submitted via Web forms.

It provides means to define the type of validation for each input value and then performs the verification of all the submitted values associating a configurable error message to all inputs that contain invalid values.

It supports the following types of validation:

- Value length limits
- Regular expression matching
- E-mail address format
- Fields that must be equal like passwords and confirmation
- Floating point values
- Integer values
- Empty values