ded/bonzo — pull request #91 by ryanve (2012-07-24 09:46:17+00:00)
Title: safer typechecking in .toggle() and .show()

In `.toggle()` I added a `this.length` check so that the optional callback does not get called for empty sets, and I made it so that the callback only gets called if it is function. This makes it easier to interchange jQuery and bonzo b/c the `.toggle(duration)` syntax can now be used w/o throwing an error:
```js
.toggle(null, 'block') // specify a display type w/o supplying a callback
.toggle(47) // same effect as .toggle()
.toggle(47, 'easeInBounce') // same effect as .toggle()
```
Also (a consideration) does it make sense to pass the collection as the scope of the toggle callback?