Update VE core submodule to master (caaff2c)

New changes:
d0ab5bd Localisation updates from https://translatewiki.net.
6b876bd Update OOjs UI to v0.1.0-pre (b38d485723)
caaff2c Blur contentEditable node while destroying surface

Change-Id: I4121ed82617053e8763cdc3d3aaa5ee9aa76e571
Revert "Clear selection after tearing down surface to work around Firefox bug"

Superseded by I051ef92eeea9 in VE core.

This reverts commit d68eae6c8df8785fd77b327445dbc7945f5a88e5.

Change-Id: Ie5e0a6169cfe3634e20a3b88e8aeb980b4094e10
Merge "Update VE core submodule to master (caaff2c)"
Merge "Revert "Clear selection after tearing down surface to work around Firefox bug""