Eliminate extra allocations for the std::list node instances.

Use Storage::MapUTF8() internally, don't use global variables.

Move from db/DatabaseGlue.cxx, eliminating global variable.

Users now have to call Close() explicitly.  This simplifies using the
class, as most users have automatic socket management already, and
Steal() had to be used often.

Publish the Client API, preparing to move more code into the Client
class.

Copy the according file from another project (i.e. XCSoar).  This will
allow copying more code more easily.

playlist and player_control are deprecated.

Reduce access to the global variable "g_playlist".

Remove GLib dependency from some headers.

Allocate a player_control object where needed, and pass it around.
Each "client" object is associated with a "player_control" instance.

This prepares multi-player support.

This updates the copyright header to all be the same, which is
pretty much an update of where to mail request for a copy of the GPL
and the years of the MPD project. This also puts all committers under
'The Music Player Project' umbrella. These entries should go
individually in the AUTHORS file, for consistancy.

Removed the sockaddr_to_tmp_string() hack, use
the new function sockaddr_to_string() instead.

With the GLib main loop, the client manager can install its own event
in case a client is expired.  No need for main.c to call
client_manager_expire() manually.