Update VE core submodule to master (f8f9728)

Authored by Catrope.


Update VE core submodule to master (f8f9728)

New changes:
68e20d4 Create AlignableContextItem to quickly adjust AlignableNodes
0150df2 Update OOjs UI to v0.9.3
b333fd3 FragmentInspector: Execute action on enter, rather than closing with data
2d14f7a Fix webkit column hack
be780eb Don't drop whitespace when removing empty slug paragraphs
cc19787 Split handlesOwnChildren and ignoreChildren
7f1c9a7 Localisation updates from https://translatewiki.net.

Local changes:
Add ignoreChildren to handlesOwnChildren nodes

Change-Id: Id3dc7efae8d30b6551b2fc3104ed00bc86339176