PHP5 rewrite of HTML_QuickForm and HTML_QuickForm_Controller packages.

This package provides methods to create, validate and render HTML forms.

Features:
* Supports all form elements defined by HTML standard, provides several
custom elements
* Server-side and client-side validation, several common rules provided
* Multipage forms (tabbed forms and wizards)
* Pluggable elements, rules, renderers and renderer plugins

Major advantages over PHP4 version:
* Most of the package's functionality is covered by unit tests
* DOM-like API for building the form structure, new streamlined API for
elements' values handling
* Default rendering without tables (inspired by
HTML_QuickForm_Renderer_Tableless)
* Renderer plugins for elements with complex rendering needs
* Ability to chain validation rules with 'and' and 'or'
* Client-side validation can run "live" on changing the form fields,
validation errors are displayed near the fields instead of in alert()