UAF13 — UAF::*ControlFlow not possible from most UML::ActivityNodes

By constraining UAF ControlFlows to just the associated viewpoint Actions as sources and targets we are preventing users from using the full range of UML::ActivityNodes that they could use in Process Views. Significally, ControlNodes, such as the Initial,Fork,Join,Merge,Final Nodes are all excluded but of major importance to good description and visualization.
Recommendation:
1) Either elevate UAF::*ActivityAction up to UML::ActivityNode and specifically add UML::InterruptingActivityRegion.interruptingEdge
2)or remove .source and .target constraints on UAF::ControlFlows