[bug] Shifted segmentation and image

### Description
The aim is to **display a brain segmentation overlapped on a T1 MRI image** (both Nifti) using AMI.
The problem is that the **brain segmentation appears shifted from the T1**.
However, when I load these images with Papaya web viewer, FreeView or MRView, everything is properly registered.

#### Live Demo
You can find a minimal live example here (a modified version of the example _viewers_labelmap_):
https://codesandbox.io/s/mqx57mwzlp

#### Steps to Reproduce
Please load the example with Google Chrome, I think its not working with Mozilla Firefox.
Just wait for the images to be loaded and displayed.

#### Expected Results
Image properly registered, loaded with the Papaya web viewer.

#### Actual Results
Image badly registered, loaded with AMI.js (code example given just above)

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

### Versions
- AMI: v0.22.0
- THREEJS: v0.92.23