Moved I/O alert to file reader

src/main/java/GraphDataObjectReader.java

@@ -13,6 +13,8 @@ public class GraphDataObjectReader {
             BufferedInputStream fileIn = new BufferedInputStream(new FileInputStream(filename));
                 ObjectInputStream in = new ObjectInputStream(fileIn))
         {
+            System.out.println("Reading graph data from file. This may take some time");
+            System.out.println("File I/O time is not included in results");
             data = (GraphWithMapData) in.readObject();
         } catch (FileNotFoundException | ClassNotFoundException ex) {
             ex.printStackTrace();