Stop HTTP clients from exploiting MPD via forged POST requests.

For database plugins that don't use the UpdateService.

Manipulates the playback range of a queued song.

Implement a "bulk" edit mode that postpones both UpdateQueuedSong()
and OnModified().  This way, the playlist version gets incremented
only once.  More importantly: when adding multiple songs to a queue
that consists of only one song, the first song that got added will
always be played next.  By postponing this choice, all newly added
songs get a chance to become the next song.  Fixes the second (and
last) part of Mantis ticket 0004005.

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

This case is handled already by playlist_open_in_playlist_dir() (via
playlist_mapper_open()).  And the call didn't work anyway.

Fixes assertion failure.

The string "base" is understood by locate_parse_type(), but not by
listAllUniqueTags().  The special tag type LOCATE_TAG_BASE_TYPE causes
a crash in PrintUniqueTag().

Lists files and directories.  Supports storage plugins.