Since validation is done earlier, invalid addresses are reported as with
renderError() instead of startAction("doError"). So the tests which
watch for doError are now failing (the frontend tests named
"resources/state: start with invalid requiredEmail - print error screen"
and "resources/state: start with empty requiredEmail - prints error
screen". I don't know how to make them watch for renderError() instead.

One upside of this patch is that @stomlinson told me the three-argument
to startAction("doError"..) in state.js was a bug, as it only accepts
two real arguments. Removing it is even easier than fixing it.