The "tagtypes" command now has several sub commands which can be used
to edit that mask.

Unused.

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.