code: public static Map<String, Object> revisionHistoryToJson(List<InternalDocumentRevision> history) {
          return revisionHistoryToJson(history, null, false, 0);
      }
docs: Serialise a branch's revision history, without attachments.
  See {@link #revisionHistoryToJson(java.util.List, java.util.List, boolean, int)} for details.
  @param history list of {@code InternalDocumentRevision}s.
  @return JSON-serialised {@code String} suitable for sending to CouchDB's
  _bulk_docs endpoint.