func (list LexSymbolList) Sort() LexSymbolList {
	sorter := LexSymbolSorter{
		list: list,
	}
	sort.Sort(sorter)
	return sorter.list
}
func (list LexSymbolList) Sort() LexSymbolList {
	sorter := LexSymbolSorter{
		list: list,
	}
	sort.Sort(sorter)
	return sorter.list
}
// Sort returns a sorted list of LexSymbols, sorted by Priority