Description
     Returns a name for a submit button (or an <input type="image"> control) that will invoke a specific action. This means the following: if you do
$this->addElement('submit', $this->getButtonName('foo'), 'Foo'); | 
inside the 
buildForm() 
method and the user later uses this button to submit the form, then the 
'foo' handler (added
via 
addAction()
will be called.