multiply speed by velocity controls for vrmesh/alembic

[Vance]

it would be great to have the multiply speed by velocity control like the actor node has for the shape node.  

the actor node has limits to its flexibility in terms of material handling that the shape node doesn't have.  It could be a good work around for simple crowd systems that could generate variety by using vraymultisubtexture.

[tyFlow]

Main issue with the Shape operator is that if you turn mesh speed interpolation on and have speeds of less than 1.0, RAM usage can explode due to the way it works internally. I'd rather improve the actor material assignment capabilities of tyFlow, than add features to the Shape operator that will make people more inclined to use it for these types of scenarios.