Uses a depth first search algorithm to set the component of all nodes in a component. **Unset functions only set the component and recurse on nodes whose component is currently set to the unset value. The forward and backward bools indicate the direction to use for a directed depth first search from node.

protected virtual void ComponentUnset( 
   LayeredDigraphVertex v,
   int component,
   int unset,
   bool forward,
   bool backward
)