Implemented QNX API for device "connected" status

The feature allows to know whether QBluetoothLocalDevice
is currently connected to any other device using connectedDevices() method for QNX platform.

Change-Id: Id103f66321de52c2bc63e2bdbead85f11f9108a9
Reviewed-by: Fabian Bumberger <fbumberger@rim.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>