feat(directives): remove the @Controller directive

Completely remove the deprecated Controller directive. Update the
demos to use setRootContext.

Pulled out of the first commit in #1269.
Something like

```
transformers:
- angular
    html_files:
      - file1.html
      - file2.htrm
```

But first we should wonder why it was working before and it is no more working, any idea ?