When tremor (libvorbisidec) is used, HAVE_OGGVORBIS was not defined.

This patch allows mpd to recognise the albumartist tag in the way
foobar2000 and others write it to files.

Splitted flac_copy_vorbis_comment() into flac_copy_comment() and
flac_copy_comment().

Simplify flac_copy_vorbis_comment() by moving the comment
identification code out.

Free the tag object when it turns out to be empty.  This simplifies
several functions and APIs.

tag_is_defined() checks whether there is any information in the tag
object.

Use tag_is_empty() instead.

Renamed types, functions, variables.

Calling input_curl_select() after EOF has been reached causes an
assertion failure.  This can happen if the HTTP response is empty.
Check c->eof before calling input_curl_select().

Set the "ready" flag for empty resources.

To check for early connect failures, call curl_multi_info_read() in
the constructor input_curl_open().  This fixes an assertion failure.

Copy changelog items from the upcoming 0.14.1 release.

g_queue_clear() was introduced in GLib 2.14.  Add a macro hack for
older GLib versions to emulate it.

gcc doesn't know that g_error() never returns.  Work around the gcc
warning.

g_get_user_special_dir() was introduced with GLib 2.14.  Don't use it
in older versions.

dest_size is only used in an assertion.  Remove its declaration and
move the formula into the assertion.

In NDEBUG, the parameter "decoder" is not used.

The function ipv6Supported() is not used at all when IPv6 support was
disabled at compile time.

This patch allows mpd to recognise the albumartist tag in the way foobar2000
and others write it to files.

Sorting songs by file name does not make much sense.  Most of the
time, users want to add songs in track order to the playlist.

Path names in the directory and song structs are always encoded in
UTF-8.  Don't use strcmp(), it cannot handle UTF-8 characters
properly.  Use GLib's UTF-8 aware g_utf8_collate() function for that.

I was having problems with shoutcast stream outputs before applying
the attached patch, which enlarges the shoutcast output
buffer. Ideally, this should be configurable, but this resolves the
issue for my needs.

Don't depend on the daemon's locale settings.  Comment names are
ASCII.

vorbis_parse_comment() should be a function which converts one comment
to a tag item.  It should do everything required to do the conversion,
including looping over all possible tag types.

Eliminate some duplicate code.

Always allocate a new tag object before parsing the vorbis comments;
free it when it turns out to be empty.  This simplifies the code a
bit.

Renamed functions and variables.

Make ogg_parseCommentAddToTag() return bool instead of unsigned int.

Read the id3 tags "TPE2" and "TSO2" into the "album artist" tag.

mpd uses some additional files to work, such as pid_file, state_file,
db_file, etc. when running mpd as non-root user, it is often that those
files end in ~/.mpd

in that case, we end up with 2 entries in a user's home, .mpdconf and
.mpd - which clutters homedirs.

this patch allows ~/.mpd/mpd.conf as an alternative to ~/.mpdconf,
allowing for a cleaner homedir

If a tag value is an empty string, the space after the colon was
removed by g_strchomp().  Fix this by removing the space check and
using g_strchug() on the return value.

The matchesAnMpdTagItemKey() API becomes more powerful and flexible if
the return value is the value pointer instead of a boolean.  It also
removes (invalid and dangerous) assumptions about the string from its
caller.

When a song file is deleted during database update, all pointers to it
must be removed from the playlist.  The "for" loop in
deleteASongFromPlaylist() did not deal with multiple copies of the
deleted song properly, and left instances of the (to-be-invalidated)
pointer in.  Fix this by reversing the loop.

Added TAG_ITEM_ALBUM_ARTIST.

With this patch, MPD should be able to read the (inofficial)
"ALBUMARTIST" Vorbis comment.  Implementations in other decoder
plugins will follow soon.

matchesAnMpdTagItemKey() broke when two tag items had the same prefix,
because it did not check if the tag name ended after the prefix.  Add
a check for the colon and the space after the tag name.

If http_proxy_{host, port, user, password} are provided in mpd.conf
they are not passed on to libcurl. As a result mpd cannot stream from
behind an http proxy.

The attached patch `http_proxy.patch` makes the relevant calls to
curl_easy_setopt(...) for all proxy configuration parameters, but is
only tested for host and port.