[Twisted-Python] porting twisted.spread to Python3

[Wolfgang Rohdewald]

there now is https://github.com/wrohdewald/twisted.git

branch spread-py3-7598

Not all is finished, especially utf-8 wherever Python 3
allows it, pbfailure, and handling of wired exceptions.


what should I do next to start getting this into trunk? 
Maybe

- open a ticket for porting banana
- create a branch with all commits for that
- do a pull request

I do not want to create one big patch because I think
it is helpful to have more smaller commits.


But I probably should wait with all that until 
ticket 7664 is merged.

-- 
Wolfgang