fix #1045182 readded the X-unsent param for writing mails

# Conflicts:
#	process/Email_lib/process.js

process/Email_lib/process.js

@@ -249,7 +249,7 @@ Email.prototype.getRFCmail = function ()
     //"X-Unsent" is a very badly, non-standardised header to gently ask the mail client that the mail should open in a compose-mode
     //this is mainly done for Microsoft Outlook for Windows. 
     //Thunderbird has a dinosaur-request (it's from the year 2002) to also support this: https://bugzilla.mozilla.org/show_bug.cgi?id=166541 
-    //mail.addHeader(mailId, "X-Unsent", "1");
+    mail.addHeader(mailId, "X-Unsent", "1");//readded, TODO: why has this been removed?
     
     //accoding to this entry: https://stackoverflow.com/questions/11330628/os-x-mail-open-eml-files-in-compose-mode/33224913
     //something similar exists for OS X Mail