ceylon/ceylon.language#493: Rename Range -> Span and range() -> span()
ceylon/ceylon.language#493: Fix up tests for rename Range -> Span and range() -> span()
ceylon/ceylon.language#493: Rename SizedRange -> Measure and sizedRange() -> measure()
ceylon/ceylon.language#493: Fix tests for rename SizedRange -> Measure and sizedRange() -> measure()
ceylon/ceylon.language#493: Rename Ranged.segment() -> Ranged.measure()
ceylon/ceylon.language#493: Update tests for rename Ranged.segment() -> Ranged.measure()