Make the puppet snippets follow best practices

Update the snippets to follow the best practices mentioned in the styleguide at
http://docs.puppetlabs.com/guides/style_guide.html. Updates include:

- Ensuring all strings are single quoted by default.
- All inner items end the line with a comma.
- Default file mode is a 4 digits, not three.
- Various fixes to value substitution/completions to prevent throwing empty
  strings.
Alphabetize the properties :lipstick:
Merge pull request #3 from jacobbednarz/make-snippets-follow-standards

Make snippets follow standards
Prepare 0.7.0 release