Examples are not working on master

### Description
Failed to run first example.
I just follow the steps at Developer corner section and got an Uncaught TypeError.

Not sure if I'm missing something because I haven't changed anything in the project. So it must be a bug.

#### Steps to Reproduce
Example:

1. git clone https://github.com/FNNDSC/ami.git
2. cd ami
3. yarn install
4. yarn example geometries_slice

#### Expected Results
I expected to see the example running.

#### Actual Results
```
controls.trackball.js:17 Uncaught TypeError: Class constructor rt cannot be invoked without 'new'
at new _class (controls.trackball.js:17)
at init (geometries_slice.js:137)
at ./examples/geometries_slice/geometries_slice.js.window.onload (geometries_slice.js:156)
```

### Browsers Affected
- [x] All
- [ ] Chrome
- [ ] Firefox
- [ ] Edge
- [ ] Safari 9
- [ ] Safari 8
- [ ] IE 11

### Versions
- AMI: master
- THREEJS: 129