curl: show headers in bold

The feature is only enabled if the output is believed to be a tty.

-J: There's some minor differences and improvements in -J handling, as
now J should work with -i and it actually creates a file first using the
initial name and then *renames* that to the one found in
Content-Disposition (if any).

-i: only shows headers for HTTP transfers now (as documented).
Previously it would also show for pieces of the transfer that were HTTP
(for example when doing FTP over a HTTP proxy).

-i: now shows trailers as well. Previously they were not shown at all.

--libcurl: the CURLOPT_HEADER is no longer set, as the header output is
now done in the header callback.

src/tool_getparam.c

@@ -1722,24 +1722,22 @@ ParameterError getparameter(const char *flag, /* f or -long-flag */
       }
       break;
     case 'i':
-      config->include_headers = toggle; /* include the headers as well in the
-                                           general output stream */
+      config->show_headers = toggle; /* show the headers as well in the
+                                        general output stream */
       break;
     case 'j':
       config->cookiesession = toggle;
       break;
-    case 'I':
-      /*
-       * no_body will imply include_headers later on
-       */
+    case 'I': /* --head */
       config->no_body = toggle;
+      config->show_headers = toggle;
       if(SetHTTPrequest(config,
                         (config->no_body)?HTTPREQ_HEAD:HTTPREQ_GET,
                         &config->httpreq))
         return PARAM_BAD_USE;
       break;
     case 'J': /* --remote-header-name */
-      if(config->include_headers) {
+      if(config->show_headers) {
         warnf(global,
               "--include and --remote-header-name cannot be combined.\n");
         return PARAM_BAD_USE;