Python 3 support is absent

[zxwild]

I've forked it and replaced

• iteritems() --> items()
• unichr() --> chr()
• xrange() --> range()
• print '' --> print('') etc..

And fixed some imports, but it's not tested to fit a python2, so I didn't make a pull request.

[PiotrDabkowski]

Can you make it work for bothon 2 and 3? Otherwise we can have 2 files - 1 for python 2 and another one for py3.