A helper class to facilitate generating, processing and securing HTML forms. By default, `Form`
will simply generate HTML forms and widgets, but by creating a form with a _binding object_,
the helper can pre-fill form input values, render error messages, and introspect column types.
For example, assuming you have created a `Posts` model in your application:
{{{// In controller code:
use app\models\Posts;
$post = Posts::find(1);
return compact('post');
// In view code:
<?=$this->form->create($post); // Echoes a <form> tag and binds the helper to $post ?>
<?=$this->form->text('title'); // Echoes an <input /> element, pre-filled with $post's title ?>
<?=$this->form->submit('Update'); // Echoes a submit button with the title 'Update' ?>
<?=$this->form->end(); // Echoes a </form> tag & unbinds the form ?>
}}}