model: inline superfluous "helper" methods __get_changeset_status wasn't even used and has simply been removed. Notification.__get_notification reimplemented BaseModel._get_instance, warts and all, and has been replaced by calls to that method. The rest were just needless indirection, and have been inlined.

# 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
.