[#19] Fixed failing unit tests

Test failures were due to:

- missing `vendor/README.md` file in TestAsset application. Added this, and test
  passed.
- `.gitignore` rule that we were testing meant a necessary file was not present!
  Renamed the file `.gitignore.dist`, and added setUp/tearDown functionality to
  copy it to `.gitignore` and remove it during the testing process. Test now
  passes.