files: use the web browsers built-in js history instead of native.history.js The history API is available in all web browsers we support. window.history.pushState is called to register a state that we can go back/forward to. (But contrary to native.history.js, it doesn't do any immediate processing of the state and doesn't actually navigate to it.) When navigation occurs, we get the popstate event and invoke load_state to actually load the state.

# 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
.