I have no idea why the docs think strings are better. pyinstaller wasn't
able to detect the import through the string so the code ended up being
stripped from the package. Use an explicit import to prevent that.
A possible explanation for the infrequent CTDs we've been seeing since
adding fast forward is that QWebChannel doesn't keep a reference to the
python objects that it passes to js, so if the object is GC'd before the
front end is done with it, it crashes.
We don't really like QWebChannel anyway, so this begins replacing that
with FastAPI.
