Add no_code_generation and stop_on_failure to config

fixes issue #352

This adds the following options to `phpspec.yml'

```yaml
no_code_generation: true
stop_on_failure: true
```
Fair points, will put it back.
On 11 Aug 2014 17:48, "Christophe Coevoet" <notifications@github.com> wrote:

> In src/PhpSpec/Console/Application.php:
>
> >          foreach ($config as $key => $val) {
> >              if ('extensions' === $key && is_array($val)) {
> > -                foreach ($val as $class) {
> > -                    $extension = new $class;
> > -
> > -                    if (!$extension instanceof Extension\ExtensionInterface) {
> > -                        throw new RuntimeException(sprintf(
> > -                            'Extension class must implement ExtensionInterface. But `%s` is not.',
> > -                            $class
> > -                        ));
> > -                    }
> > -
> > -                    $extension->load($container);
> > -                }
> > +                $this->loadExtensions($val);
> > +            } else {
> > +                $this->container->setParam($key, $val);
>
> Well, including unrelated changes in your PR makes it harder to revisw (I
> spent some time trying to understand why this code changed before figuring
> there was no difference in the behavior). And the usage of the container
> property would make it harder to extract the container building (currently
> setupContainer and all its helper methods are not depending on the fact
> that the container ends up being stored in $this->container)
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/phpspec/phpspec/pull/418/files#r16064734>.
>