Added missing binding case for binding literal strings to sort types, resolves #442
Subscripting code now allows indexes on relations and list relations to be comparable to the item type or a set of the item type, resolves #406
Fixed accidental merging of qualified names with unqualified names, now keeping overload sets for both, resolves #430
Merge branches 'keyword-parameters' and 'master' of https://github.com/cwi-swat/rascal into keyword-parameters