cleanup library and some basic tests. Includes, add guards to includes

library/x509write_csr.c

@@ -37,13 +37,13 @@
 #include "polarssl/oid.h"
 #include "polarssl/asn1write.h"
 
+#include <string.h>
+#include <stdlib.h>
+
 #if defined(POLARSSL_PEM_WRITE_C)
 #include "polarssl/pem.h"
 #endif
 
-#include <string.h>
-#include <stdlib.h>
-
 /* Implementation that should never be optimized out by the compiler */
 static void polarssl_zeroize( void *v, size_t n ) {
     volatile unsigned char *p = v; while( n-- ) *p++ = 0;