Reference name and group editing

Objective:

* Allow editing reference groups and names in the reference dialog

Bonus:

* Modify attribute transaction builder to support multiple attribute
  changes in a single transaction

Changes:

ve.ui.MWReferenceDialog.js
* Load ref name and group from model
* Save ref name and group, if changed, to model

ve.ui.ListAction.js, ve.ui.Transaction.test.js, ve.ce.ResizableNode.js
* Update use of newFromAttributeChange to newFromAttributeChanges

ve.dm.SurfaceFragment.test.js
* Add test for new changeAttributes method

ve.dm.InternalList.js
* Missing new line at end of file

ve.dm.Transaction.js
* Change newFromAttributeChange to accept an list of attribute changes and
  produce a single transaction that applies one or more attribute changes
  at once

ve.dm.SurfaceFragment.js
* Fix bug in getCoveredNodes where the wrong mode name was being used
* Add changeAttributes method, which applies attributes to all covered
  nodes and allows filtering of which types of nodes the attributes are
  applied to

ve.dm.MWReferenceNode.js
* Actually write key and group back to DOM
* Separate onRoot functionality into addToInternalList so it can be called
  separately (similarly onUnroot/removeFromInternalList)

ve.ce.MWReferenceListNode.js
* Clone internal item CE node before appending to avoid rendering bug.

*.php
* Add links to messages and sort them

Change-Id: Ic4121e4fcfc09265d5863af6f078cdeb77926c8e