Merge latest fixes

Author: Laurence Bank

MacOS/PNG_Test/PNG_Test/Makefile

@@ -1,13 +1,13 @@
 CFLAGS=-Wall -O2 -g -fsanitize=address,undefined
 LIBS = 
 
-all: png_demo
+all: png_test
 
-png_demo: main.o
-	$(CC) main.o -fsanitize=address,undefined -g $(LIBS) -o png_demo 
+png_test: main.o
+	$(CC) main.o -fsanitize=address,undefined -g $(LIBS) -o png_test 
 
 main.o: main.cpp
 	$(CXX) $(CFLAGS) -c main.cpp
 
 clean:
-	rm -rf *.o png_demo
+	rm -rf *.o png_test