Expand bonnie:load:mitre_bundle to allow EP/EH selection

*This pull request must be merged with the bonnie_bundler pull request projecttacoma/bonnie_bundler#5 for correct application functionality.*

#### Story ####
- https://www.pivotaltracker.com/story/show/63975288

#### Notes ####
- Updated <code>rake bonnie:load:mitre_bundle</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
- Also correctly imports the bundle such that only the corresponding <code>measures</code>, <code>patients</code>, and <code>value sets</code> are loaded via <code>bundle:import</code>
- E.g., the following commands produce the following results
    - <code>rake bonnie:load:mitre_bundle['/path/to/your/bundle-2.4.0.zip',bonnie@example.com]</code>
        - Imports and loads all <code>measures</code>, <code>patients</code>, <code>value sets</code>, and <code>results</code>
    - <code>rake bonnie:load:mitre_bundle['/path/to/your/bundle-2.4.0.zip',bonnie@example.com,eh]</code>
        - Imports and loads all **EH** <code>measures</code>, <code>patients</code>, <code>value sets</code>, and <code>results</code>
    - <code>rake bonnie:load:mitre_bundle['/path/to/your/bundle-2.4.0.zip',bonnie@example.com,ep]</code>
        - Imports and loads all **EP** <code>measures</code>, <code>patients</code>, <code>value sets</code>, and <code>results</code>
    - <code>rake bonnie:load:mitre_bundle['/path/to/your/bundle-2.4.0.zip',bonnie@example.com,banana]</code>
        - Imports and loads all <code>measures</code>, <code>patients</code>, <code>value sets</code>, and <code>results</code>