Support annotations directly on delegates

[rodionmoiseev]

Consider the following use case:

interface Window{
  @En("Dialog title")
  Dialog dialog();
}

interface Dialog{
  @En("OK")
  String ok();
}

Currently, in order to get dialog title, one has to create an explicit Dialog.title() method, where as, it would be nice to be able to use the delegating method itself for holding the title. Thus, one would call System.out.println(window.dialog()) and that would print "Dialog title".