title: issue with programmatically added constraits
body: <p>i use Masonry library to programmatically add constraints. Basically i simple add constrants from my button bot -> bottom of view (equal to 20 points) and from my button top -> bottom of label (equal 20). However, even when constraints values are equal, you can easily see that space from button to bot is lesser then space from button to top (meaning buttom -> top text). Here is code for set constraints:</p>
  
  <pre><code>[self.readNextButton mas_makeConstraints:^(MASConstraintMaker *make) {
  
          make.right.equalTo(self.containerForNewsText.mas_right).with.offset(-20);
          make.bottom.equalTo(self.containerForNewsText.mas_bottom).with.offset(-20);
          make.top.equalTo(self.truncatedNewsText.mas_bottom).with.offset(20);
  
      }];
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/VrL8q.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/VrL8q.png" alt="enter image description here"></a></p>
  
  <p>Why is that happen? Maybe there is some feature involving button frame? Im not sure if that needed, but there is button created code:</p>
  
  <pre><code>    self.readNextButton = [UIButton new];
      self.readNextButton.titleLabel.adjustsFontSizeToFitWidth  = YES;
      self.readNextButton.backgroundColor = [UIColor whiteColor];
      [self.readNextButton setTitleColor:[UIColor colorWithHexString:@"#60aabf"] forState:UIControlStateNormal];
      self.readNextButton.titleLabel.lineBreakMode = NSLineBreakByClipping;
      self.readNextButton.titleLabel.font = [UIFont fontWithName:@"Roman" size:14];
      [self.readNextButton setTitle:@"Читать дальше" forState:UIControlStateNormal];
      [self.view addSubview:self.readNextButton];
  </code></pre>