Update VE core submodule to master (d2a5cb5)

New changes:
548655a Add focusing state flag to ce.Surface when programatically focusing
d7819ae Remove unnecessary overflow:hidden from block slug style
d2a5cb5 Update OOjs UI to v0.1.0-pre (d4baf57069)

Change-Id: If964c13b1f131d2450013c7a93060fc143bd50c9
Merge "Update VE core submodule to master (d2a5cb5)"