Update VE core submodule to master (b5a0269)

New changes:
20d9764 Move window managers to sub folder
d69c2fa Update OOjs UI to v0.2.3
62aa941 Use complex change logic if there are changes not at the selection

Change-Id: I063a38268c96db614f8870c65cdc0ed62fb96e27
Merge "Update VE core submodule to master (b5a0269)"