move copyCorsor() and copy() to concrete classes (with concrete return type)
remove unnecessary localize() and getIntPosition() overrides and format code.
formatting
Update IterableSubIntervalBenchmark:
* make the walkThrough methods compute something such that the loops
  cannot be optimized away.
* benchmark array and planar img alternatively such that
  de-optimization hits all benchmarks
SubIntervalCursor check: require that requested interval is contained. Add more comments.
fix IterableTransformBuilder logic for iterating slices.
Almost-copy of IterableSubIntervalBenchmark that avoids polymorphic calls into the walkThrough methods