AngularJS: Update to 1.3

I looked through the changelog and couldn't find any changes that were relevant
to us. If you can think of any, please open a PR!
i.e. = that is, e.g. = for example
Merge pull request #1054 from Trott/ie-vs-eg

i.e. = that is, e.g. = for example
Implement backend API to Angular.
done
done -> completed
fix tests
just use GET /api/todos to check if api exists
allow overriding learnJson
fix source link in learn bar
modularize api & localStorage