Use new macros for all TLS/DTLS tests

sed -i -e 's/\([^ ]*transport\) == MBEDTLS_SSL_TRANSPORT_DATAGRAM/MBEDTLS_SSL_TRANSPORT_IS_DTLS( \1 )/' -e 's/\([^ ]*transport\) \(!= MBEDTLS_SSL_TRANSPORT_DATAGRAM\|== MBEDTLS_SSL_TRANSPORT_STREAM\)/MBEDTLS_SSL_TRANSPORT_IS_TLS( \1 )/' library/ssl_*.c

New sizes (see 2nd-previous commit for measuring script):

```

both
   text    data     bss     dec     hex filename
   1820       0       4    1824     720 debug.o (ex library/libmbedtls.a)
      0       0       0       0       0 net_sockets.o (ex library/libmbedtls.a)
    548       0       0     548     224 ssl_cache.o (ex library/libmbedtls.a)
  11155       0     596   11751    2de7 ssl_ciphersuites.o (ex library/libmbedtls.a)
  17156       0       0   17156    4304 ssl_cli.o (ex library/libmbedtls.a)
    460       0       0     460     1cc ssl_cookie.o (ex library/libmbedtls.a)
  17649       0       0   17649    44f1 ssl_srv.o (ex library/libmbedtls.a)
    800       0       0     800     320 ssl_ticket.o (ex library/libmbedtls.a)
  39286      60       0   39346    99b2 ssl_tls.o (ex library/libmbedtls.a)
  88874      60     600   89534   15dbe (TOTALS)

DTLS-only
   text    data     bss     dec     hex filename
   1820       0       4    1824     720 debug.o (ex library/libmbedtls.a)
      0       0       0       0       0 net_sockets.o (ex library/libmbedtls.a)
    548       0       0     548     224 ssl_cache.o (ex library/libmbedtls.a)
  11155       0     596   11751    2de7 ssl_ciphersuites.o (ex library/libmbedtls.a)
  16948       0       0   16948    4234 ssl_cli.o (ex library/libmbedtls.a)
    460       0       0     460     1cc ssl_cookie.o (ex library/libmbedtls.a)
  17437       0       0   17437    441d ssl_srv.o (ex library/libmbedtls.a)
    800       0       0     800     320 ssl_ticket.o (ex library/libmbedtls.a)
  38147      60       0   38207    953f ssl_tls.o (ex library/libmbedtls.a)
  87315      60     600   87975   157a7 (TOTALS)

TLS-only
   text    data     bss     dec     hex filename
   1820       0       4    1824     720 debug.o (ex library/libmbedtls.a)
      0       0       0       0       0 net_sockets.o (ex library/libmbedtls.a)
    548       0       0     548     224 ssl_cache.o (ex library/libmbedtls.a)
  11155       0     596   11751    2de7 ssl_ciphersuites.o (ex library/libmbedtls.a)
  14912       0       0   14912    3a40 ssl_cli.o (ex library/libmbedtls.a)
    460       0       0     460     1cc ssl_cookie.o (ex library/libmbedtls.a)
  15868       0       0   15868    3dfc ssl_srv.o (ex library/libmbedtls.a)
    800       0       0     800     320 ssl_ticket.o (ex library/libmbedtls.a)
  27619      60       0   27679    6c1f ssl_tls.o (ex library/libmbedtls.a)
  73182      60     600   73842   12072 (TOTALS)
```
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 0c587e9..214ac5e 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -452,7 +452,7 @@
     */
 
     *olen = 0;
-    if( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ||
+    if( MBEDTLS_SSL_TRANSPORT_IS_TLS( ssl->conf->transport ) ||
         ssl->negotiate_cid == MBEDTLS_SSL_CID_DISABLED )
     {
         return;
@@ -734,7 +734,7 @@
      * When responding to a verify request, MUST reuse random (RFC 6347 4.2.1)
      */
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
-    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+    if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) &&
         ssl->handshake->verify_cookie != NULL )
     {
         return( 0 );
@@ -785,7 +785,7 @@
         return( 1 );
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
-    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+    if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) &&
             ( suite_info->flags & MBEDTLS_CIPHERSUITE_NODTLS ) )
         return( 1 );
 #endif
@@ -926,7 +926,7 @@
      * DTLS cookie
      */
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
-    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
+    if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) )
     {
         if( ssl->handshake->verify_cookie == NULL )
         {
@@ -1021,7 +1021,7 @@
      * an actual need for it.
      */
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
-    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
+    if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) )
         offer_compress = 0;
 #endif
 
@@ -1137,7 +1137,7 @@
     ssl->state++;
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
-    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
+    if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) )
         mbedtls_ssl_send_flight_completed( ssl );
 #endif
 
@@ -1148,7 +1148,7 @@
     }
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
-    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+    if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) &&
         ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
@@ -1252,7 +1252,7 @@
     size_t peer_cid_len;
 
     if( /* CID extension only makes sense in DTLS */
-        ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ||
+        MBEDTLS_SSL_TRANSPORT_IS_TLS( ssl->conf->transport ) ||
         /* The server must only send the CID extension if we have offered it. */
         ssl->negotiate_cid == MBEDTLS_SSL_CID_DISABLED )
     {
@@ -1645,7 +1645,7 @@
     }
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
-    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
+    if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) )
     {
         if( buf[0] == MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST )
         {
@@ -2996,7 +2996,7 @@
     ssl->state++;
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
-    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
+    if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) )
         mbedtls_ssl_recv_flight_completed( ssl );
 #endif
 
@@ -3628,7 +3628,7 @@
         return( ret );
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
-    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+    if( MBEDTLS_SSL_TRANSPORT_IS_DTLS( ssl->conf->transport ) &&
         ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING )
     {
         if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )