Add virtual selection overlays to the same parent as the annotations view

Virtual selection overlays were being added to the office:document
element. This is inconsistent with most other non-document UI overlays.
Re-add the shadow cursor's selection on document undo

This is an interm fix until a "grown-up" undo stack arrives.

The current undo implementation for single user replaces the document
content, which causes OdfCanvas to entirely clear and replace all
children in the parent element.

Most overlays are unaffected as they are re-added when the cursor is
redraw. The shadow cursor is not an added cursor however, and so after
an undo it stops functioning.
Merge pull request #190 from peitschie/undo-shadow-cursor

Re-add the shadow cursor's selection overlays on document undo
== Op-ify member data handling ==

* New operations: OpAddMember, OpRemoveMember,
OpUpdateMember.
* Member data is now handled in a memberDataManager
instance inside OdtDocument.
* Any operations must be executed only if a member
is present within this model.
* All polling code for member data has been removed;
colors, names, and images now instantly update
whenever a member data operation is executed.
* Added relevant entries to the OT Matrix.
Remove terrible hack for setting the dc:creator
field's text in an annotation; now that we
have first-class access to member data,
we can set this value directly within
OpAddAnnotation.
Changes related to MemberData w.r.t Annotations:

* Remove old artifacts from AnnotationViewManager.
* Make OpUpdateMember updated all dc:creator elements
that have been labelled with an editinfo:memberid attribute.
* Add tests for member data operations in conjunction with
annotations.
* Add a member "Alice" by default in OperationTests.js,
so that annotations in tests can also have an author name.