Allows the client to get the first, or oldest, record added to the log.
Accepts no parameters.
Returns a single record(mapping of column names to values).
>>>#Get first record of log.
>>>datalog.get_first_record()
{'_seq': 0, 'timestamp': 1247091795.0, 'Time Value': 1247091793.271832, 'Relay2': 0,'Relay1': 0}