Handle send intents

So I found this app in the play store and gave it a try.  It didn't quite do what I wanted, but when I discovered that it is open sourced here on github I decided to take a crack at modifying it.

My use case is that I want to be inside an app like Reddit Is Fun, click share on a thread, and send a gif link to gfycat to be converted and loaded.  I'm not sure that my solution is complete, but it works for me and I figured I would offer it as a proof of concept.  I think this would make gfycat better.

Let me know what you think.
Better to use `intent.getCharSequenceExtra()` here; some apps send that instead of a String.