Change 'To run' to 'To use' in all README.md files

As in:

    sgit -e 's/# To run/# To use/g' '*README.md'

This makes consistent the message for how to use the program. 'How to
use' was chosen because one can run a program just by doing './foo' but
that doesn't imply that's how to use it but the purpose of the section
is how to use it.

1987/biggar/README.md

@@ -10,7 +10,7 @@ make all
 ```
 
 
-## To run:
+## To use:
 
 ```sh
 some_command | ./biggar | od -c

1987/heckbert/README.md

@@ -11,7 +11,7 @@ make all
 On System V systems, we had to compile with `-Dindex=strchr`.
 To compile on a 16 bit machine, change 300000 to 30000.
 
-## To run:
+## To use:
 
 ```sh
 ./heckbert col < file

1987/hines/README.md

@@ -9,7 +9,7 @@ US
 make all
 ```
 
-## To run:
+## To use:
 
 ```sh
 ./hines file.c

1987/lievaart/README.md

@@ -12,7 +12,7 @@ make all
 There is [Alternate code](#alternate-code) available for if you have an old
 enough compiler.
 
-## To run:
+## To use:
 
 ```sh
 ./lievaart

1987/wall/README.md

@@ -10,7 +10,7 @@ make all
 ```
 
 
-## To run:
+## To use:
 
 ```sh
 ./wall

1987/westley/README.md

@@ -10,7 +10,7 @@ US\
 make all
 ```
 
-## To run:
+## To use:
 
 ```sh
 ./westley