Add Support For Windows

As mentioned in #76. `dist` is not a Windows friendly as unix related operations such as `cat` will fail. In order to allow it to work, I use [shelljs][https://github.com/arturadib/shelljs].  

Changes includes:
  - Add dependencies to shelljs
  - Replace unix operations with shelljs' methods
  - Add build option for Windows (`npm run-script build-win`)
  - Update README.md with instruction to build for Windows.