Linting, PEP 8 checks, Python 2 & 3 print and input, Py 2 hashbang

Although you may not update this script again, I think the best way to understand the coding conventions is 1. doing it yourself but 2. having a good example to follow. Thus, I have linted and PEP 8 checked your script, in addition to a few improvements.

All changes performed by hand, no automatic fixers used. PEP 8 accuracy provided by [http://pep8online.com](http://pep8online.com).

### Actions Performed ###
* Tabs to standard 4 space indentation
* Spaces around operators
* Line length (except for one I could do nothing with)
* Line spacing
* Removed unneeded semicolons
* Docstrings
* Space after pound sign
* Capital first letter in comment
* If block wrapping

Additionally,
* Added Python 2 hashbang (script encoding not set)
* Use Python 3 `print()` when running on Python 2 (`from __future__ import print_function`)
* Python 2 and 3 compatible user input (more information on both of these at [http://wp.me/P1V5ge-Y6](http://wp.me/P1V5ge-Y6))
* Close script using `sys.exit()` with exit code `0`

Merry Christmas, Stopsecret! :smiley: