Make fading transitions work better

Previously, a Fade transition would only affect a view if its
parent hierarchy was not also affected between the start/end states.
This caused problems for views which were removed from their parents
between scenes when their parents' visibility also changed between those
scenes. The effect would be that the transition would fade the parent...
but the child would no longer be in that parent, so the user would just see the
child view blink out.

This fix ensure that views are faded appropriately by fading them
regardless the parent hierarchy; if a view is removed from its
parent, fade it out.

Additionally, if that view has not been removed from its parent, but
its parent is no longer parented *and* scene being
transitioned from is based on a layout resource file (and thus
the views are considered temporary after transitioning), then it is
removed from its parent to be faded out in the overlay.

Also, renamed TextChange to ChangeText to be more consistent with
other transition class names.

Change-Id: I4e0e7dfc9e9d95c7a4ca586534b6d204c4f3bae0