Small changes

Compatibility fixes for Python 3.x

Installer no longer attempts to write to privileged directories

Misc improvements

- Added a CONTRIBUTING.md file
- Fixed a small indentation error
- Version bump

Improved efficiency in filesystem calls

Fixed crash in installer on Windows.

Fixed a crash on Windows

Major refactoring

Did a significant refactoring for the sake of code-clarity. Also abandoned
argparse in favor of docopt.