[emacs-w3m:13849] emacs-w3m and youtu.be

You are all probably are familiar with the existence of youtu.be as a
shortened version of youtube.com. I just now tried downloading such a
URL and found that it wasn't resolving properly. It seems that the URL
requires some modification in order to be recognized. This is done
automatically by the google/youtube servers when the sender's user-agent
is "supported" but emacs-w3m isn't one of those.

Thus, there are two solutions:

1) Change the user-agent for emacs-w3m (temporarily or permanently).
   This can be done on the command-line via M-x w3m-user-agent-change,
   or by modifying variable w3m-user-agent.

2) Have emacs-w3m auto-magically convert the URL by adding an entry to
   variable  w3m-uri-replace-alist. For example:

  (push '("\\`https?://youtube.be/\\(.*\\)"
          w3m-pattern-uri-replace "http://youtube,com/watch?v=3D\\1")
        w3m-uri-replace-alist)

I've tested both techniques with my w3m-download.el PR that uses wget
and youtube-dl as the download back-ends.

If solution #2 is desirable to the project, I'd be happy to prepare a PR
separate from the w3m-download.el PR.

=2D-
hkp://keys.gnupg.net
CA45 09B5 5351 7C11 A9D1  7286 0036 9E45 1595 8BC0



=2D-
hkp://keys.gnupg.net
CA45 09B5 5351 7C11 A9D1  7286 0036 9E45 1595 8BC0