v1.5.6
AsyncIO compression part 1 - refactor of existing asyncio code (#3021)
Coalesce Almost All Copyright Notices to Standard Phrasing
Also Pin Dockerfile Dependency Hashes
Rename "External Matchfinder" to "Block-Level Sequence Producer" (#3484)
minor: fix missing newline character in help page
[linux] Remove usage of deprecated function
Fix wrong conditions
pzstd: use c++14 without conditions
Do not test WIN32, instead test _WIN32
moved snap to /contrib
created contrib/cleanTabs