The activeSlides vector was being modified by enqueueSlide while it was being iterated in update(). enqueueSlide now raises a flag, and it is update() that now modifies the activeSlides vector.
Also added path so that if an xml file is not specified for the slide show, there are useful defaults that can still create one.
Updated the example app to reflect these changes.
Updated the example's xml file.
Added an xml file for the slide show in the example.