Refactor client using Angular

* Rebuild client using Angular
* Create led-toggle directive
* Add support for Less
* Use Bower for client dependencies
* Add client build process using Grunt and Browserify
* Add watch task to monitor changes and auto rebuild
* Uglify scripts if env = production
* Debug and source maps if env != production 
* Separate npm packages for client and server
* Move Arduino related files into arduino folder
* Update server to reference client changes
* Update readme