cli: fix '--full' option of index-create The option '-f' or '--full' is actually a flag, but the current declaration made click expect a value as argument. Instead, follow the click convention to allow --full and --no-full, to indicate it is a boolean flag, as we do in other places.

# 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
.