Make transformations also to inner classes! (this actually works, even
if inner and nested classes aren't supported by javassist).
Working with nested/inner classes works in my case (adding method
calls to each constructor/method) and I definately want those to be
transformed!

I don't know why this restriction has been in there. If it was only
because of that hint in the documentation of javassist, then we can
remove it like this. If there had been any problems with nested classes
in the past, then we should think about how we want to handle this.
Made it version 1.0.0 from 1.0.0-SNAPSHOT b/c release plugin in
projects that use this one as a dependency keeps complaining.