python 3 compatibility fixes (mostly for examples)

[jswhit]

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[ivanov]

Hi Jeff (peanut gallery comment, just came across this) - is there a reason to not use from __future__ import print_function everywhere? the sys.stdout.write looks a bit awkward.

[jswhit]

sys.stdout.write will work on python 2.5 - but since I'm using the print_function approach in some places, I may as well use it everywhere. I'll change this when I get a chance. Note that this is only for the examples, I'm don't intend to sacrifice python 2.5 compatibility in the module itself.

[ivanov]

ah right, thanks for the explanation, forgot about 2.5. Now I appreciate why once packages start supporting python3, they start to move away from anything older than 2.6, in order to keep their sanity :)