Camera.setView moves the camera further out than supported in 2D

Reported on the forum: https://groups.google.com/forum/?hl=en#!topic/cesium-dev/87kyE-NhFVU

This moves the camera further away from the map than is supposed to be allowed in 2D

``` javascript
var viewer = new Cesium.Viewer('cesiumContainer', { sceneMode : Cesium.SceneMode.SCENE2D });

viewer.camera.setView({
destination: Cesium.Cartesian3.fromDegrees(0, 0, 60000000)
});
```

Start by running the 2D Viewer example from the issue and inspect the Camera.setView entry point and its 2D destination handling. Done means the same destination no longer moves the camera farther from the map than the supported 2D limit.

Written by the indexing model from the issue text.