CoreAudio: Create an audio plugin supporting iOS and OS X

This removes the Mac audio backend that was hardcoded into QtMultimedia
and adds a new audio plugin using the CoreAudio API.

Change-Id: Ib15291825f9452a3763e0eeb281d952deb0bad3d
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@digia.com>
Reviewed-by: Christian Stromme <christian.stromme@digia.com>
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>

src/plugins/coreaudio/coreaudio.pro

@@ -0,0 +1,39 @@
+TARGET = qtaudio_coreaudio
+QT += multimedia-private
+
+PLUGIN_TYPE = audio
+PLUGIN_CLASS_NAME = CoreAudioPlugin
+
+load(qt_plugin)
+OTHER_FILES += \
+    coreaudio.json
+
+#DEFINES += QT_DEBUG_COREAUDIO
+
+HEADERS += \
+    coreaudiodeviceinfo.h \
+    coreaudioinput.h \
+    coreaudiooutput.h \
+    coreaudioplugin.h \
+    coreaudioutils.h
+
+OBJECTIVE_SOURCES += \
+    coreaudiodeviceinfo.mm \
+    coreaudioinput.mm \
+    coreaudiooutput.mm \
+    coreaudioplugin.mm \
+    coreaudioutils.mm
+
+ios {
+    HEADERS += coreaudiosessionmanager.h
+    OBJECTIVE_SOURCES += coreaudiosessionmanager.mm
+    LIBS += -framework AVFoundation
+} else {
+    LIBS += \
+        -framework ApplicationServices \
+        -framework AudioUnit
+}
+
+LIBS += \
+    -framework CoreAudio \
+    -framework AudioToolbox