hooks: set Windows stderr output mode to binary This prevents Python (or the Windows console) from replacing \n with \r\n. The extra \r made exception output show up with empty lines. Assuming we only get text and never binary data on stderr, an alternative solution could be to strip trailing whitespace ...

# requirements.txt file for use as "pip install -r requirements.txt" as a
# readthedocs compatible alternative to "pip install -e ." which is a working
# alternative to "setup.py develop" which doesn't work with Mercurial 3.7
.