Add support for annotate/blame/praise

    /**
     * Annotate content with current revision based on a diff with a previous revision.
     *
     * @param <R> type of the revision object that old metadata about the revision.
     * @param <E> type of the element to annotate (ie: String holding a line).
     * @param content the annotated content (up to the revision preceding the one given), use null to start a new
     *                blame.
     * @param revision the revision metadata to associate with the given revision.
     * @param previous the content of the previous revision to diff against the currently annotated content, use the
     *                 latest revision to start a new blame.
     * @return the updated annotated content.
     */
    <R, E> AnnotatedContent<R, E> blame(AnnotatedContent<R, E> content, R revision, List<E> previous);