link_extractor: More substitutions for the title
Add substitution for unicode apostrophe
Don't hard-code places to look for titles in FF

Before, I specified where exactly in the JSON structure an open and a closed
tab can expect to have the `url` and `title`.

Now, I search the whole structure recursively.
Add additional split (' : ') to defancify titles
Handle images / PDFs / ... better
More docstrings, less unused imports
Don't error out on non-url-looking urls
Rename confusing variable
Fix defancifying of titles

Remove symbols from title parts before searching for them in the site

In the case of wikipedia, the title would be split into eg:
['Flubber', 'Wikipedia, the free encyclopedia'], and then compared to
'en.wikipedia.org'

But 'wikipedia,' (note the comma) is not in 'en.wikipedia.org'.  So now
punctuation is removed from the title when comparing to the site.
Don't defancify title if none of the parts are similar to the site