This patch completes the configuration support.

Don't call g_error(), which will abort the process and dump core.

This patch does not affect all the config_get_X() functions.  These
need some more refactoring.

This option was deprecated by the 0.15 release.  This patch makes this
option invalid.

The "group" configuration option is similar to "user" as it
sets user set what group MPD shall run as.  With "user"
option, MPD changed GID to the GID of the user, however,
more control could be desired.

Moreover, the patch changes the way of checking whether no
setuid(2)/setgid(2) is required -- previously user names
were compered, now UID and GIDs are compered (ie. the one we
already have (getuid(2)/getgid(2)) with the one we want to
change to).

A recent change to the boolean parser introduced a bug: instead of
using the block_param's value with get_bool(), we passed param->value
(which is always NULL in this case).

Add this option to the user's manual.

Moved the check from config_get_block_param().  Detect the duplicate
parameter when it's added, not when it's queried.

Instead of returning an artificial three-state integer, return a
"success" value and put the boolean value into a "bool" pointer.
That's a little bit more overhead, but an API which looks more
natural.

Initialize the config_entries array at compile time.  This is not only
faster, but also smaller.

This function is unused.

Due to padding, this takes the same amount of memory.

The top-level "mixer_device" and "mixer_control" options have been
deprecated by MPD 0.15, and it's safe to remove them in MPD 0.16.

Renamed all remaining CamelCase functions.

strcasecmp() is locale dependent, making it a bad choice for internal
string comparisons.

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.

Allow input plugins to configure with an "input" block in mpd.conf.
Also allow the user to disable a plugin completely.

Define the GLib logging domain in the following libraries: conf,
daemon, event_pipe, log.

For better debugging aid when something goes wrong, log the name of
the effective configuration file.

The "decoder" configuration block may contain the configuration of one
decoder plugin.

The function config_add_param() allows adding new configuration
parameters.

Return the default value in the conf_get_block_*() functions when
param==NULL was passed.

This simplifies a lot of code, because all initialization can be done
in one code path, regardless whether configuration is present.

All config_get_block_*() functions should accept constant config_param
pointers.

This convenience function parses a configuration value into a positive
integer.  It aborts if parsing fails.

"Stickers" are pieces of information attached to existing MPD objects
(e.g. song files, directories, albums).  Clients can create arbitrary
name/value pairs.  MPD itself does not assume any special meaning in
them.

Eliminate some more getBlockParam() invocations.

This replaces lots of getBlockParam() invocations.

Use config_get_path() instead in mapper.c.

config_get_path() is an simpler interface than parseConfigFilePath().

Don't return a writable pointer.

No "force" parameter, pass a default value instead.

Renamed functions, types, variables.