Make a release

[reftel]

There have been some fixes on master since last release (e.g. the generification of CallExecutorBuilder in PR #78 ). Could you please make a release, so that users can get an artifact with those fixes?

[elennick]

let me see what i can do @reftel - it's been a while since ive released and i just have to see if i still have the build set up to do so

[santanusinha]

I love the interface but the type erasure in the builder is causing issues. Will it be possible to release this?