VE-1613: Support for MediaGallery paremeter - expand - in VE

Changes seem pretty significant and this is because it's not only support for displaying but also for changing value of expand. So if you process transaction similar to this: ve.dm.Transaction.newFromAttributeChanges(ve.instances[0].view.model.documentModel, 8, {expand:false} you will notice that diff looks correct.

https://wikia-inc.atlassian.net/browse/VE-1613