datasketches-cpp-4.0.0

This is a major release with some API-breaking changes

• Common sorted view used by all quantiles sketches with simultaneous support for both inclusive and exclusive modes
• The default mode for all methods for querying quantiles sketches was changed from exclusive to inclusive
• The mode is now a method parameter, not a template parameter
• Queries of empty quantiles sketches such as get_rank() and get_quantile() will throw an exception now (returned NaN for floating point types before)
• SerDe was removed from class templates and added to the relevant method templates (such as serialize and deserialize)
• Support for comparator instances in quantiles sketches
• Support for equality operator instance in frequent items sketch
• Added operator-> to iterators over quantiles sketches