Added support for mapping from child indices on side refinement to child indices in volume refinement.
Changed return type for getChildEntities() to vector, and added getChildEntitiesSet().  The rule with getChildEntities() is supposed to be that it's in the order of the children in the appropriate RefinementPattern.
Support in MeshTopologyTests for getChildEntitiesSet.
A largely complete test of h-BasisReconciliation for the "side" case.  All that remains is to change the call to BasisReconciliation, and to write the corresponding method implementation (test-driven development at work)...