Add Bluetooth code (for iOS 5.0+).

Control process:
1. Install the project on iOS Device1 and Device2. Turn bluetooh function on.
2. Tap "Create BluetoothServer" on Device1.
3. Tap "Search" and then "Join BluetoothServer" on Device2.
4. Tap "Send Message" on either of the devices.
5. Tap "Disconnected BluetoohServer".