Expand Measures::BundleLoader.load() to allow EP/EH selection

*This pull request must be merged with the bonnie pull request projecttacoma/bonnie#71 for correct application functionality.*

#### Story ####
- https://www.pivotaltracker.com/story/show/63975288

#### Notes ####
- Updated <code>Measures::BundleLoader.load()</code> to take an additional, optional, input specifying whether **<code>ep</code>** or **<code>eh</code>** or both types of measures should be loaded from the specified bundle
- Added simple unit tests for verifying <code>ep</code> and <code>eh</code> measure loading
- E.g., the following commands produce the following results
    - <code>Measures::BundleLoader.load('/path/to/your/bundle-2.4.0.zip', bonnie@example.com)</code>
        - Loads all <code>measures</code>
    - <code>Measures::BundleLoader.load('/path/to/your/bundle-2.4.0.zip', bonnie@example.com,nil,nil,nil,'eh')</code>
        - Loads all **EH** <code>measures</code>
    - <code>Measures::BundleLoader.load('/path/to/your/bundle-2.4.0.zip', bonnie@example.com,nil,nil,nil,'ep')</code>
        - Loads all **EP** <code>measures</code>
    - <code>Measures::BundleLoader.load('/path/to/your/bundle-2.4.0.zip', bonnie@example.com,nil,nil,nil,'banana')</code>
        - Loads all <code>measures</code>