Card.io as a Fragment implementation

[glaubergp]

Hi fellow Card.ioers :)

I've worked on implementing cardio as a fragment over the last 3 weeks so I could integrate it on my company's product. I've essentially removed all CardIOActivity references from other classes(CardScanner, OverlayView, etc) and created a couple of Interfaces. Then, it's become more dynamic as it was just a matter of implementing those interfaces in all related classes and passing them as parameter when constructing those classes.

For instructions on how to create the fragment please read the header in CardIOFragment.

I'm creating this pull request as I see you guys use that, which is good so please review my code and please let me know. I hope I can help and contribute to this stellar SDK. Seriously, this thing rocks! Lastly, I've tested SampleApp and it worked.

You may reach out to me at [email protected]

Cheers