Use print() function in both Python 2 and Python 3

[cclauss]

A partial solution to https://trac.torproject.org/projects/tor/ticket/32791

Legacy print statements are syntax errors in Python 3 but print() function works as expected in both Python 2 and Python 3.

xrange() was removed in Python 3 in favour of an iterator-base version of range().

[coveralls]

Pull Request Test Coverage Report for Build 7885

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 63.391%

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Totals
Change from base Build 7876:	0.02%
Covered Lines:	49994
Relevant Lines:	78866

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💛 - Coveralls

[teor2345]

Thanks for this PR.

We track reviews using our Trac ticket system, and we don't always notice GitHub PRs straight away.

If you put a link to the PR on the ticket (or open a new ticket in Core Tor/Tor), and put the ticket in needs_review, then we'll review your PR in the next week or two.

I've put the link for this PR here:
https://trac.torproject.org/projects/tor/ticket/32791#comment:2