Maps from pow-edit, pow-core, and Typescript 1.3

- Refactor pow2 to use pow-core for its base game functionality, which removes code duplication across pow projects.
- Upgrade to Typescript 1.3 for much faster build times.
- Update maps with latest versions from pow-edit.  Support multiple layers for rendered tile maps and collision and feature interaction.

https://github.com/justindujardin/pow-core