Replace g_strchug() calls with a cheaper implementation.

Use the functions song_save() and song_load() to use the same format
as in the database file for those songs which need the tags.

While this is not useful for the database, it may become useful for
reusing this code for the state file.

After we've been hit by Large File Support problems several times in
the past week (which only occur on 32 bit platforms, which I don't
have), this is yet another attempt to fix the issue.

Convert a string into a tag_type enum.

Clear the colon.  This simplifies all attribute parsers, because they
can now use strcmp() instead of strncmp().

Fix a minor memory leak.

Changed songvec_load() to song_load().  Added start and end markers
for each song.  Removed the "key" line, it's redundant.

Use a single GString buffer object in all functions loading the
database.  Enlarge it automatically for long lines.  This eliminates
the maximum line length for tag values.  There is still an upper limit
of 512 kB to prevent denial of service, but that's reasonable I guess.

The line buffer had a fixed size of 5 kB, and was allocated on the
stack.  This was too small for some users.  As a hotfix, we're
increasing the buffer size to 32 kB now, allocated on the heap.  In
MPD 0.16, we'll switch to dynamic allocation.

Renamed functions.

When a song was in the database twice (which shouldn't happen), and
the first song had no tag items, MPD calledd tag_free(NULL).  Add a
check to that source location, and an assertion to tag_free().

Use GLib the logging functions g_debug(), g_error() instead.

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.

Renamed numOfItems to num_items.

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.

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.

Replaced myFgets() with fgets() + g_strchomp().

CamelCase is ugly, rename the functions.

CamelCase is ugly...  rename all functions.

Provide separate constructors for creating a remote song, a local
song, and one for loading data from a song file.  This way, we can add
more assertions.

Again, a data type which can be forward-declared.

The struct can be forward-declared by other headers, which relaxes the
header dependencies.

songvec_for_each() has locking, use it instead of manually iterating
over the songvec items.

We already know if a song is a URL or not based on whether it
has parentDir defined or not.  Hopefully one day in the future
we can drop HTTP support from MPD entirely when an HTTP
filesystem comes along and we can access streams via open(2).