Util: added specialised version of Tuple.spanFrom for ceylon/ceylon-compiler#996
Util: added specialised version of Tuple.spanFrom for ceylon/ceylon-compiler#996

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