operator [minpaths] - backtracking in breadth-first over single path working. SetStreamMultiplierIsolatedVariants.java and  SetStreamMultiplierInterrelatedVariants.java outfactored from SetStreamMultiplier.java. SetStreamMultiplierIsolatedVariants.java uses IteratorCrossProductTest.java and IteratorCacheTest.java [ as of corporate dff319eaa8e74c49479e372ef8f687fc9111a283 ]