A quick and dirty fix for gapi not loading in time for ember-simple-auth

This commit is probably not something that should be merged into the main branch, but it makes it work for now, so I can continue work with implementing ember-simple-auth
Initial changes.
Converted ember-gdrive to an ember-cli addon

Storypad App works with this version of ember-gdrive. However, cleanup and script organization is still required.
Moved store-extensions initializer to app folder.
Removed library script. Modifying the Application class doesn't seem to be necessary.
Moved auth to addon/lib
Removed unnecessary dependencies from bower.json and package.json

* package.json is now completely clear of any dependencies.
* bower.json now has a few dependencies added. These are typical ember-cli addon dependencies and most of them seem to be used for running tests.
Merge pull request #12 from coderly/conversion-to-ember-cli-addon

Conversion to ember cli addon functionally done. The three remaining tasks will be created as separate issues, as agreed. This resolves #11.