SlicingIterableInterval: Removed SlicingService

SlicingService is now an Op
SlicingIterableInterval: Renamed HyperSlice to Slice
Renamed HyperSlice to Slice
IterableIntervalMapperP: Fixed major bug!

Didn't set outCursor to min.
IterableIntervalMapperP: Fixed formatting
Merge branch 'master' of https://github.com/imagej/imagej-ops
ThreadedMapperTest: Fixed test

still require to pass null parameters for optional inputs.