Removed Makefile

I moved the functionality to the `scripts` part of `package.json` and updated the `README` accordingly.

This has the additional benefit of:
* Working on Windows without having to have Cygwin installed.
* Not having to have `component` installed globally.

If you're OK with the change I can go ahead and send pull requests with the same change on the other [suitcss](https://github.com/suitcss) repositories that could benefit from it.