removes moves, makes iterators assignable
removes moves, makes iterators assignable

tempbottle/cppitertools,ryanhaining/cppitertools,jkhoogland/cppitertools,jkhoogland/cppitertools,ryanhaining/cppitertools,tempbottle/cppitertools,jkhoogland/cppitertools,tempbottle/cppitertools,ryanhaining/cppitertools