Avoid GLib.

Prepare for adding state.

Replaces GLib's GError.

Deprecated.

This plugin is horrible code, I mean it.  Last year, I tried hard to
fix it, but I figured would take less time to do a full rewrite.
Given that I don't even have any device that supports RAOP, I can't do
that properly.  After 16 months, nobody volunteered for fixing it.
Hereby, I delete it, because having no RAOP plugin is better than
having this mess.  Sorry.

The other audio_format attributes are not used.

Provide _lock() and _unlock() to wrap all accesses from the mixer
plugin.

Use these instead of exposing the internal roar_t struct.

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.

Don't let the mixer plugin "override" the libpulse callbacks.
Instead, add a "mixer" attribute to the pulse_output struct, and call
the mixer on all interesting events.

This is a complete rewrite of the PulseAudio output plugin.  It uses
the asynchronous API, which gives us more control over everything.
Additionally, it connects to the PulseAudio server on startup, and
keeps this connection up while MPD runs.  During pause, instead of
closing the stream, it enables "cork".

This allows the mixer object to access its associated audio output
object.