Merge pull request #487 from morrme/igdiamond

diamond: add hint to @Ignore annotations

exercises/diamond/src/test/java/DiamondPrinterTest.java

         assertThat(output, is(singletonList("A")));
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testTwoByTwoDiamond() {
         List<String> output = diamondPrinter.printToList('B');
                                      " A ")));
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testThreeByThreeDiamond() {
         List<String> output = diamondPrinter.printToList('C');
                                      "  A  ")));
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testFiveByFiveDiamond() {
         List<String> output = diamondPrinter.printToList('E');
                                      "    A    ")));
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testFullDiamond() {
         List<String> output = diamondPrinter.printToList('Z');