[MJAVADOC-387] Handle JDK8 -Xdoclint Add proper handling of -Xdoclint. Option is only evaluated if Java 1.8+ is used otherwise a warning is issued. Due to a limitation in Modello, it cannot simply enabled by <doclint /> because it is umarshaled to null instead of "". One has to use <doclint>all</doclint> explicitly.