earliest and latest dates unused in ShiftingTransformProvider and InterpolatingTransformProvider
The earliest and latest dates appear in the constructors of
ShiftingTransformProvider and InterpolatingTransformProvider,
but are not used anymore. They are just passed from
ShiftingTransformProvider to InterpolatingTransformProvider
and only stored in InterpolatingTransformProvider without any use for
them, except being serialized and deserialized.
These parameters can be safely removed, and the constructors being deprecated.
(from redmine: issue id 356, created on 2017-08-23, closed on 2017-11-25)