remove dead urls, clean up readme

Vulnerabilities_and_Exploits/Memory_Exploits/C-codes/getshadd.c

@@ -0,0 +1,12 @@
+// usage: ./getshadd ENVVAR BINARY
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int main(int argc,char *argv[]){
+        char *ptr;
+        ptr=getenv(argv[1]);
+        ptr+=(strlen(argv[0])-strlen(argv[2]))*2;
+        printf("%s will be at %p\n",argv[1],ptr);
+        return 0;
+}