Implement Python 2.7 compatibility

- Add 'optionparser' backport as a dependency when installing with Python 2
- Use Python 2.7.6 as default version when building with Python 2
- Include pylauncher in MSI when building with Python 2
Improve handling of ZIP files in Python 2
Stylistic fixes
Fix typo in copymodules
Remove explicit Python versions from example configurations
Reinstate explicit Python version for PyQt example
Merge pull request #9 from jbaiter/py27

Implement Python 2.7 compatibility