Use install instead of cp

According to the explanation found here:
http://en.chys.info/2009/05/install-vs-cp-and-mmap/ , it is better to
use `install' than `cp'. This is because, supposedly, `cp' opens the
new file in write-only mode and just overwrites it, whereas `install'
unlinks it first and then replaces it, making sure that running
programs don't start acting strangely.

src/Makefile

@@ -7,6 +7,6 @@ baps1: main.o
 main.o: main.c
 	$(CC) -c main.c
 install: baps1
-	cp baps1 $(INST_PATH)/baps1
+	install baps1 $(INST_PATH)/baps1
 clean:
 	rm baps1 *.o