Add UMD wrapper, remove separate AMD version

Related PRs in [Backbone.Marionette](https://github.com/marionettejs/backbone.marionette/pull/1189) and [Backbone.Wreqr](https://github.com/marionettejs/backbone.wreqr/pull/39).

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**Changes:**
- Remove AMD version
- Add UMD wrapper
  - update Gruntfile
  - update component.json
  - update package.json

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**UMD Details**

- AMD
  - `return Backbone.ChildViewContainer`
  - `Backbone.ChildViewContainer` is defined
- CommonJS
  - `module.exports = Backbone.ChildViewContainer`
  - `Backbone.ChildViewContainer` is defined
- Browser
  - `Backbone.ChildViewContainer` is defined

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Let me know if this pull request needs anything else. Thanks!