mail : add setSubject method

git-svn-id: https://svn.fournier38.fr/svn/ProgSVN/trunk@2927 bf3deb0d-5f1a-0410-827f-c0cc1f45334c

mail.php

@@ -946,6 +946,16 @@ class mail
     return reset ($from);
   }
 
+  /** Set the subject
+    * @param string In UTF8
+    */
+  public function setSubject ($subject)
+  {
+    $this->setHeader ("Subject",
+                      $this->encodeHeaders ("Subject", $subject,
+                                            "quoted-printable"));
+  }
+
   /** Set the Date
     * @param string $date In RFC 2822 format
     */