Conversion to (X)HTML5, Mobile-friendlier style, cleanups and new content

Here are the recent updates for Shlomi Fish’s Homepage.

1. Most of the site's pages have been converted to XHTML5, which is the newest standard.

2. The site's style has been made more mobile-friendly (so-called responsive web design). There may be some issues left.

3. The site is now hosted with an https:// URL, for pleasing some browsers which prefer TLS / HTTPS.

4. An announcement of version 4 of Python was published on 1 April 2019.

5. There is a new list of sites I maintain.

6. I've mirrored the essay “Your Programming Language Must Suck”.

Hope you enjoy all that!