This release includes the following changes:
- addition of Quantiles sketch: the algorithm is largely obsolete vs KLL but this provides compatibility for existing sketches
- support for serde instances in all relevant sketches; class-level templates are now marked deprecated
- greater API consistency across quantiles, KLL, and REQ
- all three support a new public get_sorted_view() interface
- all three support rank and quantile queries with an optional inclusive mode
- cmake minimum version bump to 3.16
- Kolmogorov-Smirnov test for KLL and classic Quantiles, also available in python
- code cleanup and bugfixes