(SMTP) support DATA better in the server and make sure to "escape" CRLF.CRLF

sequences in uploaded data. The test server doesn't "decode" escaped dot-lines
but instead test cases must be written to take them into account. Added test
case 803 to verify dot-escaping.

lib/smtp.c

@@ -639,6 +639,7 @@ static CURLcode smtp_done(struct connectdata *conn, CURLcode status,
   struct SessionHandle *data = conn->data;
   struct FTP *smtp = data->state.proto.smtp;
   CURLcode result=CURLE_OK;
+  ssize_t bytes_written;
   (void)premature;
 
   if(!smtp)
@@ -653,6 +654,15 @@ static CURLcode smtp_done(struct connectdata *conn, CURLcode status,
     conn->bits.close = TRUE; /* marked for closure */
     result = status;      /* use the already set error code */
   }
+  else
+    /* TODO: make this work even when the socket is EWOULDBLOCK in this call! */
+
+    /* write to socket (send away data) */
+    result = Curl_write(conn,
+                        conn->writesockfd,  /* socket to send to */
+                        SMTP_EOB,           /* buffer pointer */
+                        SMTP_EOB_LEN,       /* buffer size */
+                        &bytes_written);    /* actually sent away */
 
   /* clear these for next connection */
   smtp->transfer = FTPTRANSFER_BODY;