Builds a <wd:submit> widget. A submit is an action that terminates
the current form. It can either require the form to be valid (in which case it will
be redisplayed if not valid) or terminate it without validation (e.g. a "cancel" button).
The "validate" attribute can have the value true or false
and determines if the form is to be validated (defaults to true).
author: Sylvain Wallez version: CVS $Id: SubmitDefinitionBuilder.java 433543 2006-08-22 06:22:54Z crossley $