after v4 release:
[ ] only show action for folders or topics that have images in them (p4a.subtyper?)
  [ ] handle default items properly
[ ] support push, flash, KenBurns transitions
[ ] easier integration w/ e.g. lightbox?
[ ] slideshow portlet?

dependent on Aeron's javascript library:
[ ] better resizing for multiple aspect ratios
[ ] fix minor details of 'click to start' feature
  [ ] play/pause button is wrong initially
  [ ] clicking on a thumb should either start slideshow or not show loader indefinitely
