Many README.md files updated

Formatting and other notes. Many more need to be checked for this but I
wanted these changes out of the way of git status to try and clean my
working changes.

2004/gavin/README.md

@@ -16,7 +16,7 @@ make
 ### To run:
 
 ```sh
-./prog
+./gavin
 ```
 
 ### Try:
@@ -59,7 +59,7 @@ sh
 Can have several shell windows:
 
 ```sh
-vi gavin.hint
+vi README.md
 ./prim
 ```