Update VE core submodule to master (f7fa420)

New changes:
9371f89 Add local image to demo
be862da Add VE logo to repo and use in image demo and for branding demo page
a2c53ab Factor out wordbreak detection code and run it for simple insertions too

Change-Id: I1be861a69a1cd6eb1e163ac15b18b6d92973ed60