ToDo

- Lightbox: indicators: 
	- start/end (a-la ImageGrid.Viewer)
	- next/prev
	- count
	- selection
- Gallery: Adaptable image justification in grid
	- Can we make this passive??? (i.e. CSS only)
	- Make more accurate -- align right side to pixel...
- Gallery: Spacial navigation (up/down/left/right)
	- auto focus current image iff the gallery is visible
		- handle focus / tabindex (???)
	- option: .loop_images
	- Up/Down: might be a good idea to select an image based on 
	  longest border instead of closest center (current)...
- Gallery: PageUp/PageDown, home/end + allow page navigation
- Gallery: focus visible (if no current and partially scrolled)...
- Gallery/Lightbox: Selection of images (space / ctrl-a / ctrl-d / ctrl-i)
	- Lightbox: show selection marker
- Gallery: constructor (list of urls)
- Gallery: views
	- "make view from selection"
	- close view
	- multiple view stack
- Gallery: drop images
- Gallery: drag to sort
- Gallery: remove image
- Gallery: serialize / deserialize
- Lightbox: navigation (keyboard / mouse)
- Lightbox: fullscreen mode
- Gallery: element (???)
- ...