Such as for downloading hashtag feeds, as discussed in #666 and contributed by
@e2tovar.
Also change comment color to grey in codesnippets in documentation.
Now we use an own, mobile-first, responsive sphinx theme based on Bootstrap 4.
It makes navigation on the very long "Python module instaloader" page a lot
easier. Also, it looks better.
This solves all the problems we had with sphinx-bootstrap-theme.
