rebaseall info out of date

[Warren Young]

This paragraph in the rebase package README:

> Note that rebaseall is only a stop-gap measure.  Eventually the rebase
> functionality will be added to Cygwin's setup.exe, so that rebasing will
> happen automatically.

...should be rewritten.  I propose: "You should not need to run 
rebaseall by hand.  setup.exe has done so automatically at the end of 
each installation since Mumble 2012."  (May?  April?)

A similar thing is going on in FAQ item 4.44.  I think that FAQ item 
should be split in two, with all the rebasing related stuff answering a 
new FAQ item, "Why does Cygwin need rebasing?", refocused on talking 
about what setup.exe/rebaseall now does automatically and why.  FAQ item 
4.44 will then talk about the remaining reasons fork() can fail, and 
their possible fixes.

And while I'm proposing work for other people :) is there a better 
reason program usage info is in the README instead of man pages, besides 
lack of time or interest?  In trying to answer the question "Why do we 
need rebasing?" for myself, I first tried "man rebase".  (Yes, I did 
eventually answer the question to my satisfaction.)