Added 'aktt_follow_text' filter to "Follow Me on Twitter" text

I've added the `aktt_follow_text` filter to the "Follow Me on Twitter" text in `views/widget.php`. This allows us to modify the "Me" to "Us", when the twitter account is a company account. We use it like so:

```
function aktt_filter_follow_text() {
  return __( 'Follow us on Twitter', 'uf' );
}
add_filter( 'aktt_follow_text', 'aktt_filter_follow_text' );
```