title: textViewDidChange is not call when change UITextView.inputView?
body: <p>I drag a <code>UITextView</code> and hook up delegate with <code>File's Owner</code>.<br>
  The <code>textViewDidChange</code> is called only with default keyboard, but nothing happen when input text from my keyboard. </p>
  
  <p>How to enable delegate of <code>UITextView</code> when set its <code>inputView</code> to a custom keyboard?</p>
  
  <p>Here is my code</p>
  
  <p>ViewController.m</p>
  
  <pre><code>-(void)viewDidLoad{
      self.myKeyboard = [[[NSBundle mainBundle] loadNibNamed:@"MyKeyboard" owner:nil options:nil] objectAtIndex:0];
      [self.myKeyboard setTextView:self.textView];
  }
  
  #pragma mark TestViewDelegate
      - (void)textViewDidChange:(UITextView *)textView{
          NSLog(@"TextDidChange: %@",textView.text);
      }
  </code></pre>
  
  <p>MyKeyboard.h</p>
  
  <pre><code>@interface MyKeyboard : UIView
  @property (weak,nonatomic) id&lt;UITextInput&gt; textView;
  -(void)setTextView:(id&lt;UITextInput&gt;)textView;
  @end
  </code></pre>
  
  <p>MyKeyboard.m</p>
  
  <pre><code> -(void)setTextView:(id&lt;UITextInput&gt;)textView{
          _textView = textView;
          if ([textView isKindOfClass:[UITextView class]])
              [(UITextView *)textView setInputView:self];
          else if ([textView isKindOfClass:[UITextField class]])
              [(UITextField *)textView setInputView:self];
      }
  </code></pre>