Issue #493: Rename Range -> Span and range() -> span()
Issue #493: Fix up test for rename Range -> Span and range() -> span()
Issue #493: Rename SizedRange -> Measure and sizedRange() -> measure()
Issue #493: Rename Ranged.segment() -> Ranged.measure(), also the type parameter Span -> Subrange since Span is now the name of a class.
Issue #493: Update tests for Ranged.segment() -> Ranged.measure()