This is a hack around something we do extensively in Kst that we can no longer do (and *should* no longer do) in the future. Namely, attempt to de-reference a Qt container iterator that might be QContainer::end()

No more 'KstFooPtr = *_inputVector.find("SOMEFOOTHING");'

For now, I've hacked around this so I can draw a curve without specifying error bars. In the future, we'll probably want to redesign our container classes to make this easier.