Move ditaa.jar into the scripts directory.

contrib/README

@@ -40,4 +40,4 @@ SCRIPTS (shell, bash, etc.)
 
 dir2org.zsh          --- Org compatible fs structure output
 org2hpda	     --- Generate hipster pda style printouts from Org-mode
-lisp/ditaa.jar       --- ASCII to PNG converter by Stathis Sideris, GPL
+ditaa.jar            --- ASCII to PNG converter by Stathis Sideris, GPL