Bump to 3.2.0

Patch level release: bugfixes and OTP 19 support

Tag to 3.1.0

Bump to 3.0.0

Bump to beta-4

Bump to beta-4

Bump to beta-3

Bump to beta-2

Merge pull request erlang#558 from tsloughter/beta-1

update contributing, readme and app.src for beta-1

Bump to alpha-6