Format fix 1980s and 1990s README.md files

I also updated the todo.md file as I left some things out that have to
be done. I only explicitly named one thing but when I go over them as a
final pass I will address the things in question (some will require
discussion).

1991/README.md

@@ -1,30 +1,32 @@
-1991 marked the "The Eighth International Obfuscated C Code Contest"
+# 1991 marked the "The Eighth International Obfuscated C Code Contest"
 
-
-Look at the README.md file for the given winner for information
-on how to compile the winner and how to run the winning program.
+Look at the README.md file for the given winning entry for information
+on how to compile it and how to run the winning program.
 Look at the winning source and try to figure how it does what it does!
 You may then wish to look at the Author's remarks for even more details.
 
-Instructions for use: Run make to compile entries.  It is possible that
-on BSD or non-unix systems the makefile needs to be changed.
+Instructions for use: Run `make` to compile entries.  It is possible that
+on BSD or non-Unix systems the Makefile needs to be changed.
 
 This year, we did not single out an entry that was better than all of
 the rest.  We selected 3 entries that were, in our opinion, went beyond
 all of the other entries this year:
 
-	Grand Prize			by Brian Westley
-	Most Well Rounded		by Diomidis Spinellis
-	Best Of Show    		by Daniel J. Bernstein
+- [Grand Prize](westley/README.md) by [Brian
+Westley](https://www.ioccc.org/winners.html#Brian_Westley)
+- [Most Well Rounded](dds/README.md) by [Diomidis
+Spinellis](https://www.ioccc.org/winners.html#Diomidis_Spinellis)
+- [Best Of Show](brnstnd/README.md) by [Daniel J.
+Bernstein](https://www.ioccc.org/winners.html#Daniel_J._Bernstein)
 
 Name and address information are separated from the actual program
 prior to judging.  This eliminates any chance that we would bias our
 judging for/against any person or group.  In the end, we are surprised
-as you are to see who as won.  Even so, it is worth noting that
-Brian Westley has submitted a winning entry for the past 5 years!
+as you are to see who has won.  Even so, it is worth noting that
+[Brian Westley](https://www.ioccc.org/winners.html#Brian_Westley) has submitted
+a winning entry for the past 5 years!
 
-
-A few notes regarding possible changes to the contest:
+## A few notes regarding possible changes to the contest:
 
 We did not give awards to some traditional contest categories such as
 "Best Layout" or "Worst Abuse of the Rules".  We felt that to do so
@@ -33,38 +35,42 @@ been eliminated, and will likely be considered in future years.
 
 A number of entries made use of the following C pre-processor feature:
 
-	#define X define
-	#X foo bar
+```c
+#define X define
+#X foo bar
+```
 
-This is not permitted under ANSI C.  Some ANSI C compilers do allow
-this.  In the future, we do not want programs to use this feature.
-Because this request was not stated in the 1991 rules, we did not
-reject entries of this type.  However we provided more portable
-versions so that more people could compile these programs.
+This is not permitted under ANSI C.  Some ANSI C compilers do allow this.  In
+the future, we do not want programs to use this feature.  Because this request
+was not stated in the [1991 rules](rules.txt), we did not reject entries of this
+type.  However we provided more portable versions so that more people could
+compile these programs.
 
 This year we received entries that made use of the X Window System.
-This functionality is now available on many systems, we feel that
+Since this functionality is now available on many systems, we feel that
 programs that use these are now portable enough to be valid entries.
 
 We may allow programs to make use of the X Window System libs and include
 files, provided that they can operate with a system running at the level
 of at least X11r4.  Requiring the use of imake, a specific window manager,
-specific display hardware, or a specific user interface (Openl**k,
-M*tif, ...) is likely not to be allowed.  We will provide a more detailed
+specific display hardware, or a specific user interface (`Openl**k`,
+`M*tif`, ...) is likely not to be allowed.  We will provide a more detailed
 explanation of our viewpoint in next year's rules.
 
 In order to encourage more 'normal' looking C programs, we are considering
 the following change to the maximum size rule:
 
-    Your source, not counting any <space>, <tab>, and a <newline> character,
-    and not counting any ';', '{' and '}' character followed by a <newline>
-    character, must be 1536 bytes or less.  The entire source, counting all
-    characters, be 4096 bytes or less.
+```
+Your source, not counting any <space>, <tab>, and a <newline> character,
+and not counting any ';', '{' and '}' character followed by a <newline>
+character, must be 1536 bytes or less.  The entire source, counting all
+characters, be 4096 bytes or less.
+```
 
-Some thought has been given to adding some c++ categories, however this
-is not likely to happen soon.  We are waiting until c++ compilers become
+Some thought has been given to adding some C++ categories, however this
+is not likely to happen soon.  We are waiting until C++ compilers become
 common place on a wide number of systems.  We also need time to brace
-ourselves for what obfuscation c++ could wield!
+ourselves for what obfuscation C++ could wield!
 
 Be sure to wait until the 1992 rules are posted before submitting entries.
 We may fine tune the rules to reflect the some ideas above.
@@ -73,11 +79,12 @@ Please send us comments and suggestions what we have expressed above.
 Also include anything else that you would like to see in future contests.
 Send such email to:
 
-	...!{sun,pacbell,uunet,pyramid}!hoptoad!judges
-	judges@toad.com
+```
+...!{sun,pacbell,uunet,pyramid}!hoptoad!judges
+judges@toad.com
+```
 
-
-Credits:
+## Credits:
 
 We would like to thank Barbara Frezza for her role as official chef
 of the contest.  Landon Noll appreciated the opportunity to serve