Various fixes and updates

Make lines beginning (in markdown files) 'BTW' bold. Rebuilt the
respective html pages.

Slight update to abstract in two entries (1985/shapiro and
1994/shapiro). One is changing 'defines' to '#defines' and the other was
a typo fix.

Fixed make gen_next: added missing new files.

Various fixes in next/register.html (typos and other things).

2019/duble/index.html

@@ -571,7 +571,7 @@ inverse video mode, and movement escape codes, e.g. <code>xterm</code>, <code>g
 <p>The default size is the one of my xterm (see top of Makefile).
 You may set it to the full size of your terminal window by typing:</p>
 <pre><code>    make clobber fullscreen</code></pre>
-<p>IMPORTANT NOTES:</p>
+<p><strong>IMPORTANT NOTES</strong>:</p>
 <ul>
 <li><strong>The program compiled with a given size will fail to reload a drawing file
 with a different size!</strong></li>