Update VE core submodule to master (984b57a)

New changes:
6bbcd6a Localisation updates from https://translatewiki.net.
b8d8a5b [BREAKING CHANGE] The Great Selection Rewrite of 2014

Local changes:
Update to use new selection/range API

Change-Id: I5480d5c77d599c93c2d374fac88bb2fdb68b0024