Update MainContainer.js

1. line 55:
```javascript
var velocity  = Math.abs(e.deltaX / (e.timeStamp - e.startTime)),
```
Apparently e.deltaTime no longer exists.

2. line 70:
this.moveContainer(offset.x,100);
If you don't add a duration to the animation, the animation doesn't occur and the animation listeners (ln. 161) don't fire.