Caged/d3-tip — pull request #90 by ninjaPixel (2014-12-08 13:54:57+00:00)
Title: Transition on show and hide.

How about having a transition duration on .show and .hide? I find this easier on the eye.
```javascript
tip.hide = function() {
var nodel = d3.select(node)
nodel.transition()
.duration(transitionDuration)
.style({ opacity: 0, 'pointer-events': 'none' });

return tip
}
```

200ms works well:

```javascript
var tip = d3.tip()
.attr('class', 'd3-tip')
.html(function(d) { return '' + d.total + '' + ' entries' })
.offset([-12, 0])
.transitionDuration(200)
```

Great library, by the way. Thank you!