Implementation of speed dialing callList, REF 14345
The number stored in the speed dialing callist makes the outgoing INVITE is sent immediately, without awaiting a dialing delay. Number is stored into speed dialing callist when 200 OK or 486 Busy is received for it and it is not a control-code number (internal call, feature call, any call number starting with *, #). The number is deleted from the storage when 404 Not Found is received and number is in the speed dialing callist already. When the maximum size of speed dialing callist is reached, always the oldest number is removed (list is updated during calls in newest->oldest order).