Added code to compute the minimum label of a node's children on the fly while we scan the children.  Then, increasing the label become much quicker - no separate scan needed. This code should be restructured and localized with the other distance label code.
Added code to compute the minimum label of a node's children on
the fly while we scan the children.  Then, increasing the label become
much quicker - no separate scan needed.
This code should be restructured and localized with the other distance
label code.

cander/pseudoflow-solver,cander/pseudoflow-solver