Update VE core submodule to master (155f4ab)

Use new setupToolbar and setupDebugbar methods in base target.

New changes:
7ff523d Localisation updates from https://translatewiki.net.
3815224 [BREAKING CHANGE] Debug bar refactor
155f4ab Edit HTML mode in demo

Change-Id: I554ce51eae872ab0f741a913bf10394c2a8c3e52