Update VE core submodule to master (fa572a5)

New changes:
4d00221 Move hasSignificantWhitespace and handlesOwnChildren abstracts to ve.Node.
3889f14 Don't always use updateDimensionsDebounced
ea59d25 Safari copy-paste fix
537478d Make changes to comment node before apply staging stack
6dea745 Apply comment changes using fragment
20e928d Update OOjs to v1.1.3
98bbe75 Don't allow dropping inside a handlesOwnChildren node
9e87ccb Move mobile ContextItemWidget hacks into separate class
5d98528 Replace ve.getProp() and ve.setProp() with OO aliases

Change-Id: I7eb0d0eac311d9a220e7a0ce2f920788a3a2ec3c