Use ng-annotate

This PR suggests using [ng-annotate](https://github.com/olov/ng-annotate) to automatically add Angular dependency injection annotations at build time. This makes our source code nicer, and prevents creating non-working builds when developers forget to add annotations.

Note: the initial build takes longer than before, but ng-annotate is then run only on the source files that have changed. Thanks mr "GNU make".

Please review.