Proposed file formats

@kmdurand, @rmpowell77 - I've added example JSON file formats in the `file-formats` folder, and I'd like to know what you think, in terms of what would be easiest for Calchart to generate and what would be optimal for the viewer. 

Everything is subject to change! However, once we get the file formats set, it will start getting more and more trivial to actually display the animation. I've added the design stuff I wrote and drew up to the `design` folder for reference.

Basically, the "viewer" file is the one that is the most troublesome - I'm basically representing the show as a list of stuntsheet dicts, along with some other information. In particular, I'm not sure how to best display the initial position of all the dots for each stuntsheet.

Let me know what you think!