Removes staff email addresses from the repository

Removes redundant C library headers from hl library

hl/test/test_dset_append.c

@@ -11,10 +11,6 @@
  * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
-#include <math.h>
-#include <stdlib.h>
-#include <string.h>
-
 #include "h5hltest.h"
 #include "H5DOpublic.h"