Install cook tool when installing janet.

Makefile

@@ -183,6 +183,8 @@ install: $(JANET_TARGET)
 	cp $(JANET_HEADERS) $(INCLUDEDIR)
 	mkdir -p $(LIBDIR)
 	cp $(JANET_LIBRARY) $(LIBDIR)/libjanet.so
+	mkdir -p $(JANET_PATH)
+	cp tools/cook.janet $(JANET_PATH)
 	cp janet.1 /usr/local/share/man/man1/
 	mandb
 	$(LDCONFIG)