Remove QMediaImageViewer (SC break).

This class has turned out to be not very useful at this point in time.

Change-Id: Ic07132bdcd01a912a6dd1160c867979fd1307b6a
Reviewed-by: Jonas Rabbe <jonas.rabbe@nokia.com>

tests/auto/unit/multimedia.pro

@@ -34,6 +34,5 @@ SUBDIRS += \
 # these interfaces are exported.
 contains (QT_CONFIG, private_tests) {
     SUBDIRS += \
-        qdeclarativeaudio \
-        qmediaimageviewer
+        qdeclarativeaudio
 }