[HACKERS] Creation of "Future" commit fest, named 2017-07

Hi all,

As the next commit fest beginning soon, there will be no place where
hackers can park future patches for PG11~. So I have created a Future
CF named 2017-07 where you can do that.
Feel free to use it to park your future patches. The next development
schedule is undecided, so the name of this future CF may change. Or
not.
Thanks,
-- 
Michael