Update VE core submodule to master (ac4b49a)

Also update template/transclusion code for OOJS UI
OutlineControlWidget changes, and uses some of the new
functionality.

New changes:
ac4b49a Update OOjs UI to v0.1.0-pre (51f922ba17)

Change-Id: Id7a1f60cd6ce3bdaba7ccb8774563b9e81c75cad