The `e2e_test` folder in `angular2` never contained e2e tests but was
used to store utilities for writing e2e/perf tests. A better place for
them is `angular2/src/test_lib`.
Closes#855
Export files are now directly under the module folder,
e.g. `core/core.js`. With this, an import like `core/core`
won’t need a path mapping (e.g. via `System.paths`) any more.
This adds the `src` folder to all other import statements as well.