Add shortcut to rotate screen

On Ctrl+r, disable auto-rotation (if enabled), set the screen rotation
and re-enable auto-rotation (if it was enabled).

Closes #11 <https://github.com/Genymobile/scrcpy/issues/11>

server/src/main/java/com/genymobile/scrcpy/Controller.java

@@ -106,6 +106,9 @@ public class Controller {
             case ControlMessage.TYPE_SET_SCREEN_POWER_MODE:
                 device.setScreenPowerMode(msg.getAction());
                 break;
+            case ControlMessage.TYPE_ROTATE_DEVICE:
+                device.rotateDevice();
+                break;
             default:
                 // do nothing
         }