Sort includes and more cleanup and fixes in util/

mv.c

@@ -2,8 +2,8 @@
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <unistd.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 #include "fs.h"
 #include "util.h"