0.16.0: Reliability improvements, element blocker & report page button

This release makes Unclutter work better on more articles, and adds the element blocker mode to remove every distraction:

Internally, the page text detection has been significantly rewritten to avoid removing the main page text, to remove more non-text elements, and to clean up more empty space around the page headings.

For the last 5% of articles where this still doesn't work well (or where it misses some distractions), there are new buttons inside the "bug" tooltip in the top right of each page:

• Report page automatically creates a GitHub issue which I'll take a look at.
• Block elements allows you to immediately remove distracting page elements (see the gif above). This also creates a Pull-Request so everyone else gets your changes too.

See the docs for more details.

Many other things got fixed as well thanks to many bug reports by you all over the last weeks. Happy reading!