Changes with Aloha.Editor 1.2.18

Bugfix SUP-979

The file dom-to-xhtml.js has been moved from the plugin dom-to-xhtml to
‘util/dom-to-xhtml‘ to make it available to other plugins.

Bugfix SUP-1006

When using an inline element (such as an anchor) as editable,
selecting and deleting the whole contents would also remove the editable from the DOM.
This has been fixed, so that the editable itself will never be removed.