move fix thanks a file, update top level html links, rename CONTRIBUTING.md

The fix thank you's have been moved from `README.md` to
`thanks-for-fixes.md`.

**WARNING**: Some mistakes may have been made in doing this.
We presume later changes by others will correct any issues.

The `CONTRIBUTING.md` was renamed `how-to-enter.md`.

A 3rd line of links was added to top level html such as
`contact.html`, `index.html`, `judges.html`, `winners.html`,
and `years.html`.

Improved blank line use in a number (but not all) `README.md` files.

1993/vanb/README.md

@@ -6,17 +6,13 @@ ISX Corporation
 Marietta, GA 30067  
 US  
 
+
 ## To build:
 
 ```sh
 make all
 ```
 
-[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) fixed this to work with
-clang. The problem was that the third arg to main() was not a `char **`. Instead
-`O5()` (which was `main()`) is now its own function which main() calls with the
-right parameters. Thank you Cody for your assistance!
-
 
 ## To run:
 
@@ -38,6 +34,7 @@ hexadecimal and decimal numbers.
 
 What happens if you use something other than valid digits?
 
+
 ## Judges' remarks:
     
 The octal expression may contain:
@@ -57,6 +54,7 @@ one should surround the expression in single quotes.
 It is a good thing that this program consists of only one
 expression, otherwise it might become hard to understand.  :-)
 
+
 ## Author's remarks:
 
 The program does no error checking - erroneous expressions will
@@ -218,6 +216,7 @@ int octal( int intermediate )
 
 `F` and `C` work similarly.
 
+
 ## Copyright and CC BY-SA 4.0 License:
 
 This file is Copyright (c) 2023 by Landon Curt Noll.  All Rights Reserved.