credits.txt: Add github user "zombie"'s name
tree781c1a18c8e89a52d93d6a580dd2ac6b5a0daf33
drwxr-xr-x - .tx
-rw-r--r-- 35147 COPYING
-rw-r--r-- 138 MANIFEST.in
-rw-r--r-- 10717 README
drwxr-xr-x - bin
-rw-r--r-- 5022 makefile
drwxr-xr-x - po
-rw-r--r-- 7432 setup.py
drwxr-xr-x - share
drwxr-xr-x - src
drwxr-xr-x - tools