Feature 4599 - Integration of call clearing tones into iopsys voice

Added howler tones audio files and Makefile install update
to copy *.cln files into target's /usr/share/asterisk/sounds dir

sounds/Makefile

@@ -175,6 +175,7 @@ dist-clean:
 	rm -f *.tar.gz
 
 install: $(CORE_SOUND_TAGS) $(EXTRA_SOUND_TAGS) $(MOH_TAGS)
+	cp *.sln "$(SOUNDS_DIR)"
 
 uninstall:
 	rm -rf "$(SOUNDS_DIR)"