Adding default 8bit encoding if the body has non usascii in it

actionmailer/lib/action_mailer/base.rb

@@ -593,6 +593,8 @@ module ActionMailer #:nodoc:
           end
         end
 
+        m.content_transfer_encoding = '8bit' unless m.body.only_us_ascii?
+        
         @mail = m
       end
       

actionmailer/test/mail_service_test.rb

@@ -107,7 +107,7 @@ class TestMailer < ActionMailer::Base
     cc         "Foo áëô îü <extended@example.net>"
     bcc        "Foo áëô îü <extended@example.net>"
     charset    "utf-8"
-
+    
     render :text => "åœö blah"
   end