Fix unflatten() for the new methods on Callable
Fix unflatten() for the new methods on Callable

See ceylon/ceylon-compiler#1155.

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