Add handling of the situations where client side/server side validations fail.

Conflicts:

	include/wf.hrl
	src/actions/action_event.erl
	src/actions/action_validate.erl
	src/elements/forms/element_password.erl
	src/elements/forms/element_textbox.erl
	src/elements/forms/element_upload.erl
	src/elements/other/element_dropdown.erl
	src/elements/other/element_textbox_autocomplete.erl
	src/lib/wf_context.erl
	www/nitrogen.js