Add sample ani gifs to puzzle levels 1-3

- Add sample animated gifs to first 3 jigsaw levels (stored in Dashboard https://github.com/code-dot-org/dashboard/pull/834 to match how level builder will work)
- Mark existing jigsaw levels as k1

![image](https://cloud.githubusercontent.com/assets/206973/3305922/d3889c2a-f65b-11e3-8c57-432bbbdd6804.png)