code: public ViewQuery groupLevel(final int grouplevel) {
          params[PARAM_GROUPLEVEL_OFFSET] = "group_level";
          params[PARAM_GROUPLEVEL_OFFSET+1] = Integer.toString(grouplevel);
          return this;
      }
docs: Specify the group level to be used.
  
  Important: {@link #group()} and this setter should not be used
  together in the same {@link ViewQuery}. It is sufficient to only use this
  setter and use {@link #group()} in cases where you always want
  the highest group level implictly.
  
  @param grouplevel How deep the grouping level should be.
  @return the {@link ViewQuery} object for proper chaining.