Restore MG2 compatibility in onQueueComplete

Aborting the current handler and short-circuiting to exception handler ignores onQueueComplete. This broke compatibility with MG2.  We should expect onQueueComplete to fire consistently whether it is after a standard event handler or an exception event handler.

A common use case would be to share presentation configuration information that is not required until all other processing is complete, e.g.:

```
<event-handler name="ModelGlue.onQueueComplete">
	<broadcasts>
		<message name="needSiteTheme" />
	</broadcasts>
</event-handler>
```

Why put it in onQueueComplete?  Consider that some other processing might determine which theme to display in a themeable system.