View and edit popup annotations with ajax

The annotations on the right column are loaded only when the user
clicks on "show". This should reduce the time needed to load pages,
especially in edit mode.

Annotations can now be edited also directly from "view" mode.

- also put class IdStack in a separate file
- and the wrapping and popup editors in another separate file
- fixed the url label autofill which needed a delegated handler

Change-Id: I4ae543a8b6bc701f49b66ea0c64e4bac34013725
Merge "View and edit popup annotations with ajax"