Refactor API to transformers

[jakubkrolewski]

I think that the current API is not very user friendly. Using Transformers would be a better approach. What do you think?
http://blog.danlew.net/2015/03/02/dont-break-the-chain/

[akarnokd]

You could contribute it but I'm afraid I can't release it myself. Therefore, I suggest you build it in a separate project and release that to maven.