Custom click events now allow access to Event object, thus default
actions can be prevented, if branch elements contain elements with
default actions

Change-Id: I3e6b17ef46526e7f7ec61afb786ea6128d8d54b8
Buttons are rendered as button elements instead of input elements of
type button

Change-Id: I20fe32ffb002c36dee1858f5fb15e5e78ec7966a