Add keep_to option to control where To: recipients are copied on group-reply (To: or Cc:).

author: Jan Palus

diff -urN mutt-1.5.23.orig/send.c mutt-1.5.23/send.c
--- mutt-1.5.23.orig/send.c	2014-10-12 16:55:39.680846728 +0200
+++ mutt-1.5.23/send.c	2014-10-12 16:55:52.104179682 +0200
@@ -557,7 +557,11 @@
     if ((flags & SENDGROUPREPLY) && (!in->mail_followup_to || hmfupto != M_YES))
     {
       /* if(!mutt_addr_is_user(in->to)) */
-      rfc822_append (&out->cc, in->to, 1);
+      if (option (OPTKEEPTO)) {
+        rfc822_append (&out->to, in->to, 1);
+      } else {
+        rfc822_append (&out->cc, in->to, 1);
+      }
       rfc822_append (&out->cc, in->cc, 1);
     }
   }
diff -ur mutt-1.5.23.orig/init.h mutt-1.5.23/init.h
--- mutt-1.5.23.orig/init.h	2014-10-12 17:17:05.716118306 +0200
+++ mutt-1.5.23/init.h	2014-10-12 17:24:08.119438749 +0200
@@ -1344,6 +1344,12 @@
   ** from your spool mailbox to your $$mbox mailbox, or as a result of
   ** a ``$mbox-hook'' command.
   */
+  { "keep_to", DT_BOOL, R_NONE, OPTKEEPTO, 0 },
+  /*
+  ** .pp
+  ** Controls where recipients from ``To:'' list go on group-reply. If \fIset\fP
+  ** they are copied to ``To:'' otherwise to ``Cc:''.
+  */
   { "locale",		DT_STR,  R_BOTH, UL &Locale, UL "C" },
   /*
   ** .pp
diff -ur mutt-1.5.23.orig/mutt.h mutt-1.5.23/mutt.h
--- mutt-1.5.23.orig/mutt.h	2014-10-12 17:17:05.722784972 +0200
+++ mutt-1.5.23/mutt.h	2014-10-12 17:24:50.006104137 +0200
@@ -391,6 +391,7 @@
   OPTIMPLICITAUTOVIEW,
   OPTINCLUDEONLYFIRST,
   OPTKEEPFLAGGED,
+  OPTKEEPTO,
   OPTMAILCAPSANITIZE,
   OPTMAILCHECKRECENT,
   OPTMAILDIRTRASH,