Partition a list into equally sized pieces, including last smaller parts
    http://stackoverflow.com/questions/5129102/python-equivalent-to-clojures-partition-all

def partition_all(n, iterable):
    """Partition a list into equally sized pieces, including last smaller parts
    http://stackoverflow.com/questions/5129102/python-equivalent-to-clojures-partition-all
    """
    it = iter(iterable)
    while True:
        chunk = list(itertools.islice(it, n))
        if not chunk:
            break
        yield chunk