Roadmap 1.0 #127

This is a tracking issue for what we would expect for a 1.0 release.

Features

• REQ sketch #90
• Implement Theta Sketch #30
• KLL sketch implementation #150
• Tracking Issue for TupleSketch #156
• feat: impl densitysketch #62
• (Idea) XorFilter feat: add xor filter #208
• (Idea) DDSketch
• (Idea) UDDSketch

... and any sketch that other impls already support.

API Design

• Consider refactor: introduce hash_value for compatible hashing #118 (comment)