Update VE core submodule to master (c4ce5ee)

New changes:
c4ce5ee Update OOjs UI to v0.1.0-pre (466a8762ac)

Update changes:
* Remove manager arugment from window constructors
* Use this.$content instead of this.frame.$content
* Use this.getDir() instead of this.frame.getDir()
* this.loading is now a promise, not a boolean

Change-Id: Ia83449a60078dd24ea4f976221c0859e5a121279