feat(avatars): profile images

Getting there! Feel free to start looking @shane-tomlinson @pdehaan.

Still needs:
- [ ] profile-server client
- [ ] progress indicator screen
- [ ] unit tests for camera view
- [ ] unit tests for cropper widget
- [x] circular overlay on cropper
- [ ] functional tests
This seems a bit janky, updating navigator.getMedia like this. Is this to have the getMedia function called in the correct context? If so, you can always do something like: 

```
  var getMedia = _.bind((...), navigator);
```