I love your plugin. Great idea. Easy to use!
I think you should remove a 'space' from your plugin though. I understand that this space allows for a nice space between the icon and the text, but I'm a designer and I'd like to control this space with css instead of space characters...
It's on line 83, character 115:
$newtext = '<i class="'.implode( ' ', $fontawesome_classes ).'"></i><span class="fontawesome-text"> '.$text.'</span>';