audio: Move audioaggregator base class to a library

It's useful enough already to be used in other elements for audio aggregation,
let's give people the opportunity to use it and give it some API testing.

https://bugzilla.gnome.org/show_bug.cgi?id=760733

gst/audiomixer/Makefile.am

@@ -4,7 +4,7 @@ ORC_SOURCE=gstaudiomixerorc
 include $(top_srcdir)/common/orc.mak
 
 
-libgstaudiomixer_la_SOURCES = gstaudiomixer.c gstaudioaggregator.c gstaudiointerleave.c
+libgstaudiomixer_la_SOURCES = gstaudiomixer.c gstaudiointerleave.c
 nodist_libgstaudiomixer_la_SOURCES = $(ORC_NODIST_SOURCES)
 libgstaudiomixer_la_CFLAGS = \
 	-I$(top_srcdir)/gst-libs \
@@ -14,9 +14,10 @@ libgstaudiomixer_la_CFLAGS = \
 libgstaudiomixer_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
 libgstaudiomixer_la_LIBADD =  \
 		$(top_builddir)/gst-libs/gst/base/libgstbadbase-$(GST_API_VERSION).la \
+		$(top_builddir)/gst-libs/gst/audio/libgstbadaudio-$(GST_API_VERSION).la \
 		$(GST_PLUGINS_BASE_LIBS) -lgstaudio-@GST_API_VERSION@ \
 		$(GST_BASE_LIBS) $(GST_LIBS) $(ORC_LIBS)
 libgstaudiomixer_la_LIBTOOLFLAGS = $(GST_PLUGIN_LIBTOOLFLAGS)
 
-noinst_HEADERS = gstaudiomixer.h gstaudioaggregator.h gstaudiointerleave.h
+noinst_HEADERS = gstaudiomixer.h gstaudiointerleave.h
 

gst/audiomixer/gstaudiointerleave.h

@@ -27,7 +27,7 @@
 #include <gst/gst.h>
 #include <gst/audio/audio.h>
 
-#include "gstaudioaggregator.h"
+#include <gst/audio/gstaudioaggregator.h>
 
 G_BEGIN_DECLS
 

gst/audiomixer/gstaudiomixer.h

@@ -26,7 +26,7 @@
 
 #include <gst/gst.h>
 #include <gst/audio/audio.h>
-#include "gstaudioaggregator.h"
+#include <gst/audio/gstaudioaggregator.h>
 
 G_BEGIN_DECLS