Python 3 support

[mahmoudhossam]

I know it might be a bit too early for this, but I think the sooner we start doing this the better.

There's not much code to port, and if we start now, we'll have it working for both python versions with little to no time difference.

[kennethreitz]

+1

[jkeyes]

FYI I ran the tests with Python 3.3 and they passed.

[dtrckd]

Hi,

python3 failed on basestring, line 37:

 if isinstance(obj, basestring):
      return False

It should be fixed easily.

Thanks !

[CrabbyPete]

if I pip install I don't get the python3 version