Extract and browse the URLs contained in an email (urlview replacement)

 urlscan searches for URLs in email messages, then displays a list of
 them in the current terminal. It is primarily meant as a replacement
 for urlview, which it improves upon in the following ways:
 .
  * urlscan understands email encodings such as quoted-printable;
    urlview does not.
  * urlscan extracts and displays the context surrounding each URL.