changed the date formatter a bit

xchart/src/main/java/com/xeiam/xchart/internal/chartpart/DateFormatter.java

@@ -99,7 +99,7 @@ public class DateFormatter {
         datePattern = "HH:mm";
       }
       else if (timeUnit == HOUR_SCALE) {
-        datePattern = "dd-HH";
+        datePattern = "HH:mm";
       }
       else if (timeUnit == DAY_SCALE) {
         datePattern = "MM-dd";

xchart/src/test/java/com/xeiam/xchart/DateFormatterTest.java

@@ -91,7 +91,7 @@ public class DateFormatterTest {
     gridStepHint = (long) (span / 1000 * 74);
     timeUnit = dateFormatter.getTimeUnit(gridStepHint);
     stringValue = dateFormatter.formatDate(value, timeUnit);
-    assertThat(stringValue, equalTo("13-21"));
+    assertThat(stringValue, equalTo("21:25"));
 
     // week
     value = 1358112317000L;