Add platform.js to Miscellaneous

This adds [platform.js](https://github.com/bestiejs/platform.js), a nice platform detection library.

Here is some data that you can get with it:

- The name of the platform (e.g. Google Chrome, Node.js, etc.)
- The version of the platform
- The rendering engine (of the browser; e.g. Gecko, Trident, etc.)
- The manufacturer of the product (e.g. Apple)
- The name of the product (e.g. iPhone, Kindle, etc.)
- The name of the operating system (e.g. iOS 7.0, Mac OS X 10.7.2, etc.)
- The architecture the operating system is build for (e.g. ia32, etc.)