Bug 1072811 - [Bluetooth] BluetoothHelper APIv2 support

* patch bluetooth_helper
* revice bluetooth mockup
* add uitest/HW/bluetooth for demo
I would like to suggest we watch `mozBluetooth.onattributechanged` event before access `mozBluetooth.defaultAdapter`. It will ensure that we are ready to listen to `onattributechanged` event. Then, we try to trigger Gecko::Bluetooth to get the instance of default adapter in the first time.