Release new version

[pwim]

I noticed the most recent version, v4.0.3, is rather old, and there have been several commits since it, including the redirect support introduced in #135. It'd be awesome if a new version could be released based off the current master.

[chadlwilson]

Hello @fredjean - would it be possible to cut a new version here? is there help needed?

There are some fixes like #162 that are needed for later Ruby compatibility, and it'd be better to be able to depend on a released version rather than a git hash off master.

It looks like the unreleased changes currently are this diff which doesn't look too bad?