Show the number of answers printed and the duration of a query (#110)

## What is the goal of this PR?

We added statistic information to the UI about how many answers were printed and how long did the query take. 

## What are the changes implemented in this PR?

We added some statistic data at the end of the `printCancellableResult `:
 - answers count ;
 - duration of the query.

Author: Vlad Ganzha

GraknConsole.java

@@ -45,6 +45,8 @@
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Paths;
+import java.time.Duration;
+import java.time.Instant;
 import java.util.Iterator;
 import java.util.List;
 import java.util.function.Consumer;
@@ -231,16 +233,22 @@ private void runQuery(Grakn.Transaction tx, String queryString) {
     }
 
     private <T> void printCancellableResult(Stream<T> results, Consumer<T> printFn) {
+        long counter = 0;
+        Instant start = Instant.now();
+
         try {
             boolean[] isCancelled = new boolean[1];
             terminal.handle(Terminal.Signal.INT, s -> isCancelled[0] = true);
             Iterator<T> iterator = results.iterator();
             while (!isCancelled[0] && iterator.hasNext()) {
+                counter++;
                 printFn.accept(iterator.next());
             }
         } finally {
             terminal.handle(Terminal.Signal.INT, Terminal.SignalHandler.SIG_IGN);
         }
+        Instant end = Instant.now();
+        printer.info("answers: " + counter + ", duration: " + Duration.between(start, end).toMillis() +" ms");
     }
 
     public static void main(String[] args) {