Feature/testing framework

Implements a testing framework...

- [x] Uses Travis CI
- [x] Performs `foodcritic`, `rubocop`, and `chefspec`
- [x] RSpec/chefspec tests for most resources

```
Finished in 7.72 seconds
15 examples, 0 failures

ChefSpec Coverage report generated...

  Total Resources:   18
  Touched Resources: 15
  Touch Coverage:    83.33%

Untouched Resources:

  bash[download-jce-zipfile]         hadoop_wrapper/recipes/jce.rb:46
  bash[unzip-jce-zipfile]            hadoop_wrapper/recipes/jce.rb:53
  bash[copy-jce-files]               hadoop_wrapper/recipes/jce.rb:63
```