Update VE core submodule to master (55a5cdc): use new ve.ui.Dialogs and ve.ui.Inspectors

Move various bits of code from initialize to setup as required.

MWDialog is now useless so use ve.ui.Dialog directly.

New changes:
0b2d03f [BREAKING CHANGE] Pass fragments, not surfaces, to windows (reprise)
0101ac4 Update OOjs UI to v0.1.0-pre (ac6848398c)

Change-Id: I0fae3e5ff2bd0da5b74c244af226b07b1f5883bd