Maintain selection during insertion and deletion when possible, and d…
…eselect when not possible. Give the user more control over selection and scrolling.
Reuse image views.
On insertion, don't scroll beyond the end of the contents.
Scroll when dragging.
Row insertion, plus some more bug fixes.
Row deletion, and a couple bug fixes.
Lazy loading of images.
Row height is now a publicly exposed property.
Shift other images on the fly while we're dragging.
Handle drag cancellation much better.
Views reposition when you drag them around.
Dragging and snapping into place.
Notify delegate when selected image is tapped.
Touching an image now selects it.
Sidebar takes a delegate, which tells it how many rows to display, wh…
…at's in them, etc.
Create HSSidebarView class.