ocr-numbers: add hint to @Ignore annotations

exercises/ocr-numbers/src/test/java/OpticalCharacterReaderTest.java

         assertEquals("0", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderRecognizesSingle1() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(
         assertEquals("1", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderReturnsQuestionMarkForUnreadableButCorrectlySizedInput() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(
         assertEquals("?", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderThrowsExceptionWhenNumberOfInputLinesIsNotAMultipleOf4() {
         expectedException.expect(IllegalArgumentException.class);
         ));
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderThrowsExceptionWhenNumberOfInputColumnsIsNotAMultipleOf3() {
         expectedException.expect(IllegalArgumentException.class);
         ));
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderRecognizesBinarySequence110101100() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(
         assertEquals("110101100", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderReplacesUnreadableDigitsWithQuestionMarksWithinSequence() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(
         assertEquals("11?10?1?0", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderRecognizesSingle2() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(
         assertEquals("2", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderRecognizesSingle3() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(
         assertEquals("3", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderRecognizesSingle4() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(
         assertEquals("4", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderRecognizesSingle5() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(
         assertEquals("5", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderRecognizesSingle6() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(
         assertEquals("6", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderRecognizesSingle7() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(
         assertEquals("7", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderRecognizesSingle8() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(
         assertEquals("8", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderRecognizesSingle9() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(
         assertEquals("9", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderRecognizesSequence1234567890() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(
         assertEquals("1234567890", parsedInput);
     }
 
-    @Ignore
+    @Ignore("Remove to run test")
     @Test
     public void testReaderRecognizesAndCorrectlyFormatsMultiRowInput() {
         String parsedInput = new OpticalCharacterReader().parse(Arrays.asList(