[author] Added p2.js 0.5.0

Added p2.js 0.5.0 from NPM https://www.npmjs.org/package/p2

Direct links:
[p2.js@0.5.0](https://raw.githubusercontent.com/schteppe/p2.js/9fb751e0e9ea0a5fa219690a3e25669eccd61b81/build/p2.js)
[p2.min.js@0.5.0](https://raw.githubusercontent.com/schteppe/p2.js/9fb751e0e9ea0a5fa219690a3e25669eccd61b81/build/p2.min.js)

The same version is tagged "v0.5.0" on Github: https://github.com/schteppe/p2.js/tree/v0.5.0