Update VE core submodule to master (dc01df0)

New changes:
d02cf3d Fix simulation of .prepend() in ve.ce.BranchNode#onSplice
c19fa38 [BREAKING CHANGE] Remove generated content node wrappers

Local changes to remove classes attached to GC nodes

Change-Id: Ide82c96db4803ef59d398788b46fa5d7fb9a2476
Merge "Update VE core submodule to master (dc01df0)"