documentation around expected key types

3.1.0 changelog

Merge pull request dgrijalva#77 from dgrijalva/release_3_0_0

Release 3.0.0

release notes

version history update

version history

Merge pull request dgrijalva#74 from patbaker82/ecdsa

Add ECDSA signatures

version notes for 2.2.0

version 2.1.0