Since DCTC 0.75.0, a Berkeley database is used. This database is stored in
"$HOME/.dctc/bDB". Most of the time, DCTC provides no function to read/alter
table content because the BerkeleyDB allows concurrent access.

Currently, the following tables are in this database:

* unwanted_user: this table contains the list of "annoying" users and what to do
                 when an event from one of these users occurs.
                 In this database, the key is the user nickname. the value is
                 a set of one or more flags separated by pipe (|) without any
                 space. 
                 Available flags are: IGNORE_PMSG (ignore private message)
                                      IGNORE_SRCH (ignore search query, only for passive search)
                                      IGNORE_SREP (ignore search replay)
                                      IGNORE_XFER (don't make transfers with this user (UL & DL))
                                      IGNORE_SLOT_LIMIT (user having this flag set can always start
																	a download, even if no download slot is available
                                                   Note: this flag is only taken into account for
                                                   file transfer, not for share list)

* unode: this table contains the list of all UNODE linked to the local one.
         the key is the remote node address (IP, hostname, IP:port or hostname:port).
         the value is the structure UNODE_DATA (cf. unode.h)

* seen_hub_db: First, this database is not used by DCTC, it is managed by dc_gui. This
         table contains the list of all encountered hubs. The key is the hub address and
         the value is the line returned by hublist for this hub.

