Reinstate a proper implementation for Collection.string
Reinstate a proper implementation for Collection.string

ceylon/ceylon.language,lucaswerkmeister/ceylon.language,jvasileff/ceylon.language,jvasileff/ceylon.language,unratito/ceylon.language,lucaswerkmeister/ceylon.language,ceylon/ceylon.language,unratito/ceylon.language