This file demonstrates
an outer UITransition wrapping an inner
UITransition. Switching between Page A & Page B uses a
slide-left content transition. Inside each page, switching
between its sections uses a cross-fade content transition.
This allows you to see how a long/larger transition (page slide) can
encompass/overlap smaller fades.
transitionType = "slide-left" (content transition).transitionType = "cross-fade" (content transition).