Add ability to invoke on dynamically created file inputs

[lifeinafolder]

Currently, there doesn't seem to be a way to use it on file input elements that are adding dynamically to the DOM.

[kmilligan]

I'd also like to see this.

[brandonkm]

I think this issue is inadvertently related to issue 20.

Any file inputs dynamically added to the DOM would need a DOMNodeInserted event bound at the document level at the minimum in order to achieve this.