Update VE core submodule to b16dbb52

New changes:
c5d2909 Fix alien demo
c5fe8d7 Alien node styling
25c791a Localisation updates from https://translatewiki.net.
ff326d4 Localisation updates from https://translatewiki.net.
230800c Localisation updates from https://translatewiki.net.
91ec366 Remove margins from paragraphs inside table cells
fe72fdc Localisation updates from https://translatewiki.net.
97edf35 Fix shield CSS broken by Parsoid styles
21cddae Trigger endRelocation on focusable drag end
05d7d00 Revert "Fix shield CSS broken by Parsoid styles"

Change-Id: Ie33e187dfdacebb0dc399fbd1d78953cde72cc90