code: public static HashMap<String, ArrayList<String>> dateOffset(HashMap m, String var, String base, String offset) {
          return offset(m, var, base, offset, true);
      }
docs: Wrapper around the {@code dateOffset()} method of {@code org.agmip.common.Functions}.
  
  @param m AgMIP simulation description
  @param var Variable to output
  @param base Base date to offset
  @param offset number of days to offset
  
  @return dome compatable modification