Ships!

I added two ships (that look like rectangles right now) that are player one and two controlled by WASD and IJKL respectively.

Added a script in package.json to run the demo: `npm run dodge`
Could you break these `0.002` values into either CONSTANTS or another component? For example, each ship could have an `input-acceleration` component that simply contains `{ y: 0.002, x: 0.002 }`, which can then be referenced by including that component as a dependency.