[DGD] DGD 1.5.5

[Felix A. Croes]

I've released DGD 1.5.5 with a new feature: UDP connection handling
similar to TCP/telnet connection handling.  A UDP connection to the
server is opened by sending a UDP datagram to the server, which
triggers a call to datagram_connect() in the driver object.  This
is controlled by the optional config parameters datagram_port and
datagram_users.

Datagram channels for binary connections continue to be supported,
as long as the datagram port matches the binary port.  For example,

    binary_port = ([ "*" : 2000, "*" : 2001 ]);
    datagram_port = ([ "*" : 2000, "*" : 3000 ]);

Datagram port 2000 matches the binary port, and can be used for an
add-on datagram channel for a binary connection, as before.  Datagram
port 3000 can be used to handle inbound datagram connections that are
not associated with any binary connection.

The function open_datagram in the user object was renamed to
datagram_attach.  Additionally, the obsolete macro ST_PRECOMPILED in
status.h was replaced by ST_DATAGRAMPORTS.

The current implementation is not yet very good.  To meet my goals for
DGD, UDP connections have to be handled by a dedicated thread, as they
are in Hydra.  The low-level code is in a messy state right now,
especially the network extensions.

Regards,
Felix Croes