#227 improved styling support for columns

- support for custom css class for entire column (th + td) including
cell values
- demo for responsive columns behaviour

demo-shell-ng2/app/components/files/files.component.ts

@@ -36,6 +36,7 @@ declare let __moduleName: string;
     moduleId: __moduleName,
     selector: 'files-component',
     templateUrl: './files.component.html',
+    styleUrls: ['./files.component.css'],
     directives: [
         DOCUMENT_LIST_DIRECTIVES,
         MDL,