Show where annotations refer to in the node content

When the list of annotations is displayed the node content should have markings

The first rought version could be inserting markings into the DOM. Is a span with class="annotation annotation-nid" with no content. Style approp.

To make this work all ranges should be split into non overlapping ranges and apply multiple annotation-nid's for overlapping ranges.

But modifying the DOM has a problem when making a new annotation. The markings added are now 'in the way'.

A algorithme could be:
- on mouse up remove all markings and then add the start/end path aka range to the annotation form.