Nested log data for hpfeeds

After the session has ended a dictionary of nested logitems will be transmitted using hpfeeds. Log data contains reponse and request pdu, example:
``` python
{ 'remote': ('127.0.0.1', 58222), 'session_id': '505dd230-71c1-44f0-9136-e603448fc870',
'data': [{'request_pdu': '0300000003',
          'function_code': 3,
          'slave_id': 1,
          'response_pdu': '8302'},
          {'request_pdu': '0300009111',
          'function_code': 1,
          'slave_id': 2,
          'response_pdu': '8999'}]}
```