Type mismatch in example

Im trying to learn how to use the crate by following the [collision pipeline example](http://ncollide.org/collision_detection_pipeline/#example_1).

However, the following line, as it appears in the example, seems to no longer compile:
```rust
// Integrate the positions.
ball_pos = ball_object.position.append_translation(&(timestep * ball_velocity.get()));
```
Fails with
```rust
note: expected type `&nalgebra::TranslationBase>`
found type `&nalgebra::Matrix>`
```

Does anyone know how to fix this?