Update VE core submodule to master (426f9e4)

New changes:
1b7b23b Tests: Move …/test/… to …/tests/… to be the same as other repos
cd3fc66 Update OOjs UI to v0.1.0-pre (9cd400e3d5)
81be252 Deprecate 'live' event in favor of 'setup' and 'teardown'

Change-Id: I71277d0a3fc85541cf3a0859f58d6d522ad1db6d
Merge "Update VE core submodule to master (426f9e4)"