code: public String getOverviewReport() {
  		TreeSet<ReportEntry<V>> topLevelFailed = new TreeSet<ReportEntry<V>>();
  		fillReport(topLevelFailed, rootReport);
  		StringBuilder out = new StringBuilder();
  		for (ReportEntry<V> entry : topLevelFailed) {
  			if (entry.getSubSteps() < 100) break;
  			out.append(formatReport(entry, false));
  		}
  		
  		return out.toString();
  	}
docs: Returns a string describing, in order of 'expensiveness', the top-level failed rule chains in the parse run.