Change how <<done>> works

[tmedwards]

The current version of <<done>> isn't suitable for all uses. In particular, if being used to wait for slow DOM updates it can execute too soon.

The, likely best, solution is to switch from using the :passagedisplay event to an Engine.minDomActionDelay timeout, so we can be sure that the DOM is ready for whatever the user is up to.

For example:

setTimeout(this.createShadowWrapper(
    () => $.wiki(contents)
), Engine.minDomActionDelay);

[tmedwards]

Resolved by commit c20ffd1 .