tests: First pass on making unit tests work again. - Fix all imports - Add more helper functions to work with mock file-systems - Simplify some code by running chef directly on the mock FS - Fix a couple tests

sudo: false
language: python
python:
  - "3.4"
  - "3.5"
install:
  - "python setup.py version -f 2.0"
  - "python setup.py sdist --formats=zip"
  - "pip install dist/PieCrust-2.0.zip"
script:
  - "py.test"