round and floor incompatibilities

It turned out to be quite difficult to use round() and math.floor() while maintaining compatibility between Python 2 and Python 3. Here are some examples

Python 2

>>> round(0.5)  # rounds up, returns float
1.0
>>> math.floor(0.5)  # returns float
0.0

Python 3

>>> round(0.5)  # rounds to nearest even, returns int
0
>>> math.floor(0.5)  # returns int
0