Add UMD wrapper (bundled & unbundled), remove separate AMD version

#### Resolves #1060

This PR goes with two others in the Backbone.Wreqr and Backbone.BabySitter repos. I'll update this with links once all of the PRs are open.

***This should wait to be released until Backbone.Wreqr and Backbone.BabySitter are updated with UMD for the bundled version.***

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**Changes:**
- Remove AMD version
- Add UMD wrapper
  - update Gruntfile
  - update component.json
  - update package.json
- Creates bundled and unbundled versions
- Adds `Marionette.noConflict()` #797 

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**UMD Details**

- AMD
  - `exports = Wreqr`
  - `Backbone.Marionette` is defined
- CommonJS
  - `exports = Marionette`
  - `Backbone.Marionette` is defined
- Browser
  - `root.Marionette` is defined
  - `Backbone.Marionette` is defined

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Let me know if this pull request needs anything else. Thanks!