Add W3C DeviceOrientation Event controls and demo

Provide camera controls based on the W3C Device Orientation Event specification (http://www.w3.org/TR/orientation-event/).

A demo using these controls is included in this patch and it can be viewed directly in a browser @ http://richtr.github.io/three.js/examples/misc_controls_deviceorientation.html.

THREE.DeviceOrientationControls currently works well in the following browsers:

* Chrome Beta for Android
* Opera Beta for Android
* Firefox Beta for Android

Note: Other browsers may not yet conform to the rotation calibration described in the DeviceOrientation Event specification.

A full W3C DeviceOrientation event browser support table is available at http://caniuse.com/#feat=deviceorientation.

Detection of browser/platform deviceorientation capabilities or anomalies remain out-of-scope of this patch. Developers may test for the presence and calibration of DeviceOrientation Events prior to invoking this DeviceOrientation control.