Instagram test and Instagram node fixes

This is my work on adding the Instagram tests. A few issues might need to be sorted. I'll make comments in-line detailing these.
Why not put the two ```node.inputType === "photo"``` ifs in an ```else``` clause of the ```node.inputType === "like"```?

I'm not quite sure why you don't have separate ```handleNodeInput``` functions for the two input type cases. Particularly since you set the input event callback in an ```inputType```-based if in both cases (the second of which should probably be an else until you add another ```inputType```). I think the code would be much easier to maintain that way.