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.

2019/karns/README.md

@@ -2,25 +2,20 @@
 
 Joshua Karns  
 
+
 ## To build:
 
 ```sh
 make
 ```
 
+
 ## To run:
 
 ```sh
 ./prog < textfile_that_fits_on_the_screen
 ```
 
-[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) reported that with `-O`
-level > 0 this program segfaults (sometimes?). He's not sure why as it worked
-fine before on the same systems tested but `-O0` appears to fix the problem in
-both macOS and linux. Perhaps this is the problem that the author reported where
-it sometimes segfaults but Cody did not try debugging it. Thank you Cody for
-your assistance!
-
 
 ## Try:
 
@@ -39,6 +34,7 @@ the terminal, like:
 ./demo.sh
 ```
 
+
 ## Judges' remarks:
 
 If you typically get lost in mazes, watching this program run might -- or might
@@ -54,6 +50,7 @@ see the @ sign as well as the exclamation mark.
 A puzzle for the reader: Can you change the program to consider a diagonal
 movement as one step?
 
+
 ## Author's remarks:
 
 ### The Program:
@@ -107,6 +104,7 @@ not encountered this myself).
 - The program could be obfuscated much further.
 - The program contains some unused code and data.
 
+
 ## Copyright and CC BY-SA 4.0 License:
 
 This file is Copyright (c) 2023 by Landon Curt Noll.  All Rights Reserved.