Update git submodules
- Update extensions/VisualEditor from branch 'REL1_39' to 57a9fd7bd7204be86f5411a6b1e418d656b01cbc
- Loosen the edit link selector specificity in setupMultiTabs()
This allows VE to support even more skins with minimal or no changes to the skins themselves.
Partially reverts 75ff121b290ce0cd6b4d783fbce310887753f3cb.
Change-Id: I7536610459b7401015d4a033cc516c5d9a0ca5f1 (cherry picked from commit eb71d7710a55bd65c20c1da9cdfd20c24d782b6a)
- Loosen the edit link selector specificity in setupMultiTabs()