StringBuilder sugaring

[Janmm14]

It would be nice if you could add a StringBuilder to String concenation transformer as it makes the code mich more readable. In case the first two appends are no Strings, either cast them or add an empty String before ("" +).

[Storyyeller]

Sorry, but I barely ever have time to work on Krakatau nowadays, and there's tons of more important features that I'd want to get done before I consider this.