Screen rotation support

This PR is to implement the screen rotation (rotate the graphic layer, not the W3C screen orientation API) and device orientation API. The screen orientation API is planed in M3, and will base on this patch.

SensorProvider class is designed to abstract sensor framework and provide all sensor related notification for xwalk (currently support rotation, orientation, may support motion, compass, geolocation and gyroscope in future). TizenSystemSensor is the Tizen mobile platform specific implementation of SensorProvider interface. It is designed to not depend Tizen in build time (follow the philosophy of TizenSystemIndicator).

ScreenRotation class is an observer of SensorProvider to rotate the graphic layer. It doesn't support web API in current stage.

DeviceOrientation is another observer for device orientation event. Chromium has device orientation API support, but not on Tizen. To leverage the chromium code, DeviceOrientation object is also a provider for chromium, so it acts as a bridge to connect the SensorProvider and chromium.

I'm trying to make this PR as simple as possible, make it easy to understand and review.