force paint on bg and root element (opening transition)
Allow HTML content in slides

Also fixes zooming issue when error message is displayed (img not
loaded).
Handle links & click event in slides

(make sure that they don't trigger during/after the gestures)
Double tap zooms to 1.5x if initial zoom is less than 0.7x
disable lazy-loading if src (image) is not defined

Also, allow DOM element in slides (not just HTML string).
4.0.2 version bump & build (js, css)
docs upd