Fixed #1 - Calling API methods by passing a string to the plugin constructor method
Re #1 - Make sure the instance has the user specified method before trying to invoke it
Little bit of refactoring
Removed return statement
Merge pull request #2 from andrefgneves/master

Pass jQuery's AMD module to the factory when on AMD context
Fix API methods only called for the first item.

Example...

```html
<a href="#">Item #1</a>
<a href="#">Item #2</a>
```

```javascript
 $('a').pluginName('doSomethig');
```

...only invoked doSomething on the first anchor.