fix HTML problems related to pandoc and markdown image notation

Improve `make clobber` for `2004/anonymous`.

Instead of using this markdown element to embed an image:

```
![alt text](filename.png "Title")
```

Use a "img" HTML element with "alt", "alt", "width" and "length"
attributes:

```
<img src="filename.png"
 alt="describe the filename.png image for someone who cannot view it"
 width=PIXEL_WIDTH height=PIXEL_HEIGHT>
```

This was performed for:

```
2004/anonymous/index.html
2005/boutines/index.html
2011/goren/index.html
2012/vik/index.html
2013/birken/index.html
2013/cable1/index.html
2013/cable3/index.html
2013/hou/doc/example.html
2013/hou/index.html
2020/ferguson1/chocolate-cake.html
```

In the case of `2013/cable1/index.html` we reduce the displayed
image size by a factor for 2.  There is **NO** need to downsize the image
as this image size reduction produces a clean and sharp looking image.

In the case of `2013/hou/index.html` we reduce the displayed
image size by a factor for 2.  There is **NO** need to downsize the image
as this image size reduction produces a clean and sharp looking image.

In the case of `2020/ferguson1/chocolate-cake.html` we reduce the displayed
image size by a factor for 4.  There is **NO** need to downsize the image
as this image size reduction produces a clean and sharp looking image.

Run `make www` to perform the above.

2011/goren/README.md

@@ -23,7 +23,9 @@
 
 In the words of [René François Ghislain Magritte Magritte](http://en.wikipedia.org/wiki/Rene_Magritte):
 
-![This is not a pipe](MagrittePipe.jpg "Ceci n'est pas une pipe")
+<img src="MagrittePipe.jpg"
+ alt="The Treachery of Images, image of a pipe, titled: Ceci n'est pas une pipe"
+ width=387 height=264>
 
 One may ask the surrealist question:
 

2011/goren/index.html

@@ -160,10 +160,9 @@ Location: <a href="../../location.html#IL">IL</a> - <em>State of Israel</em> (<e
 <pre><code>    ./try.sh</code></pre>
 <h2 id="judges-remarks">Judges’ remarks:</h2>
 <p>In the words of <a href="http://en.wikipedia.org/wiki/Rene_Magritte">René François Ghislain Magritte Magritte</a>:</p>
-<figure>
-<img src="MagrittePipe.jpg" title="Ceci n&#39;est pas une pipe" alt="This is not a pipe" />
-<figcaption aria-hidden="true">This is not a pipe</figcaption>
-</figure>
+<p><img src="MagrittePipe.jpg"
+ alt="The Treachery of Images, image of a pipe, titled: Ceci n'est pas une pipe"
+ width=387 height=264></p>
 <p>One may ask the surrealist question:</p>
 <pre><code>    echo &#39;If | is just a representation of a pipe, then how can data stuff it?&#39; | ./goren</code></pre>
 <p>However if one takes a firm stand and declares:</p>