Fix #110 - implement Iterable.skippin(), taking() and by()
Fix #110 - implement Iterable.skippin(), taking() and by()

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