Add v5.7.1 to CHANGELOG

Add v5.7.0 to CHANGELOG

Add v5.6.3 to CHANGELOG

Add v5.6.2 CHANGELOG

Add v5.6.1 to CHANGELOG

Edit CHANGELOG for v5.6.0 release

Also removed previous entries because they were wrong.
TODO: Rewrite CHANGELOG

Fix indentation in release.sh

Refactor Attacker.hit and simplify tests

Simplify logic in Attacker.hit

Update CHANGELOG