fix date '0000-00-00 00:00:00.000000' parse

[seanlook]

1. when there's two datetime(6) columns in table, and the first is change to invalid date like '00-00-00 00:00:00.000000'，the second parse fail
   I think it's because that the first microsecond part is skipped when it returns None
2. Sometimes I want to convert datetime '0000-00-00 00:00:00' to exactly the string one rather than None, to keep consistent. add date_tostr argument to BinLogStreamReader to decide the behavior.
   please refer issus datetime '0000-00-00' return string '0000-00-00' #225

[the4thdoctor]

any estimate of if/when this PR will be merged? It would be nice if I could chose how to handle the datetime.

Thanks

[dongwook-chan]

@the4thdoctor
Hi again! I'm terribly sorry that I missed the issue you posted! Me and my open source team will work on this issue.
Do you still think you need this feature? How would you like control over zero datetime?

1. converter feature as pymysql provides it
2. optional parameter to BinlogStreamReader

[the4thdoctor]

Hi, yes the feature is still very needed.
I think an optional parameter to BinlogStreamReader would be great. It gives me the possibility of making the feature an opt in.
Ta!