[jdk8support] We now handle doc comments internally, alleviating the need to try and keep up with the complete rewrites of the doc comment parser from java6 to java7 to java8. Still doesn't actually work in jdk8, but only because of a last-mile issue. (we communicate the doc comment via compilationUnit.docComments but that changed types in jdk8, we just need to make a wrapper to make that work).
Updated unit tests to reflect new double-underscore default for onX. (Because single underscore generates warnings in javac8).