Deprecate twitter

We further deprecate the use of twitter.

In cases such as historic guidelines and rules, we add
a note about using Mastodon.

In cases where a tweet URL was used, we replace with
an Internet Archive link because twitter has announced
that accounts that are not used for a period of time
will be deleted.

We add a few missing deprecated_twitter information
to the author.numbers and author.cvs files.

We remove references to twitter handles (after making
sure that both author.numbers and author.cvs has the
deprecated_twitter information).  When the "_README.md_"
files have their header information generated by
a tool, such deprecated_twitter data will not be present.

2014/maffiodo2/README.md

@@ -25,8 +25,8 @@ cat image.rgb | ./prog '  .,:;!$#@'
 ## Judges' remarks:
 
 On the face of it :-) given what this program does one might wonder what makes
-this winner special.  But when you realize the source is small enough to tweet
-on twitter you understand.
+this winner special.  But when you realize the source is small enough for posting
+to social media that has a small size limit.
 
 Who will be the first to tweet this source?  How many re-tweets will such tweet
 get?  And how many people will really understand the tweet?