Implement I/O abstraction layer. Finally.

lib/zip_add.c

diff --git a/lib/zip_add.c b/lib/zip_add.c
index 75cd79d..7574762 100644
--- a/lib/zip_add.c
+++ b/lib/zip_add.c
@@ -1,6 +1,6 @@
 /*
   zip_add.c -- add file via callback function
-  Copyright (C) 1999-2012 Dieter Baron and Thomas Klausner
+  Copyright (C) 1999-2014 Dieter Baron and Thomas Klausner
 
   This file is part of libzip, a library to manipulate ZIP archives.
   The authors can be contacted at <libzip@nih.at>