Open files in 'rb' (read binary) mode to prevent useless default utf8
encoding in python3, without breaking python2 compatibility.
Reported-by: Tharre <tharre3@gmail.com>
Some people have /usr/bin/python as a link to python3. The script is
designed to work in either python2 or python3, but python3's subprocess
model defaults to close_fds=True, which closes the jobserver fds and
causes an error. Explicitly force close_fds=False to get identical
behaviour on python2 and python3.
Reported-by: Tharre <tharre3@gmail.com>
If mkdocs is running in parallel, it can get upset if one of these
files exists when it lists the directory, but doesn't exist when it
goes to generate the output. Fundamentally this is a problem in mkdocs
more than in our code, but we might as well avoid it.
These are often a good idea, but not necessary here and are distracting
to the tutorial, so let's just take them out.
Reported-by: Jeff Stearns <jeff.stearns@gmail.com>
This got... long... and complicated. But I think it's a really good
demonstration of getting redo to do complicated things elegantly. At
least, I hope it is.
