network: add mobile connection type support
network: update dbus interface about access point, return json object string if possible
network: check if connection is readonly when saving a session
network: update about wireless connection
network: hide unused dbus interface
network: add dbus property Devices, a array of device object marshaled by json
network: add dbus property Connections, collection of connection information and marshaled by json
network: rename GetConnectionPathByUuid()