Add the UNBANME privilege to allow users to unban themselves.

This is separate from the existing UNBAN privilege which applies
to all users.

Closes #331.

data/chanserv.example.conf

@@ -755,6 +755,22 @@ privilege
 	xop = "HOP"
 }
 
+/*
+ * UNBANME privilege.
+ *
+ * Used by chanserv/unban.
+ *
+ * Users with this permission can unban themself through ChanServ.
+ */
+privilege
+{
+	name = "UNBANME"
+	rank = 200
+	level = 4
+	flag = "U"
+	xop = "HOP"
+}
+
 /*
  * VOICE privilege.
  *