Update VE core submodule to master (83be91a)

New changes:
d375dc1 Restore call to dm.Surface#startHistoryTracking removed in I9f8b840c
576a4c1 Call stopHistoryTracking() when destroying ui.Surface
83be91a Update OOjs UI to v0.1.0-pre (9d291a9222)

Change-Id: I2b9f272fc9e9d8784d435a40641d655014d9cff7