Added 'email sending test' functionality.

Go to Admin -> Mail notifications and click on 'Send a test email'.
If an error occurs while sending the mail, the error message is displayed to the user.

git-svn-id: http://redmine.rubyforge.org/svn/trunk@632 e93f8b46-1217-0410-a6f0-8f06a7374b81

lang/bg.yml

@@ -69,6 +69,8 @@ notice_file_not_found: Несъществуваща или преместена
 notice_locking_conflict: Друг потребител променя тези данни в момента.
 notice_scm_error: Несъществуващ обект в склада.
 notice_not_authorized: Нямате право на достъп до тази страница.
+notice_email_sent: An email was sent to %s
+notice_email_error: An error occurred while sending mail (%s)"
 
 mail_subject_lost_password: Вашата парола
 mail_subject_register: Активация на акаунт
@@ -407,6 +409,7 @@ label_date_from: From
 label_date_to: To
 label_language_based: Language based
 label_sort_by: Sort by "%s"
+label_send_test_email: Send a test email
 
 button_login: Вход
 button_submit: Изпращане