Use the way better Symfony exception dumper.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | --
| Fixed tickets | --
| License       | MIT
| Doc PR        | --

Turns this:
![image](https://f.cloud.github.com/assets/2145092/1096074/d5f527b0-16f7-11e3-9438-f0c7779aa3ca.png)
into this if Zikula development mode is on.
![image](https://f.cloud.github.com/assets/2145092/1096079/08087f36-16f8-11e3-9823-0ff958bf6d71.png)
I really love :heart: the syntax-highlighted stack trace!

I know calling the Twig Exception Controller is hacky. But as this only happens in dev-mode I really think it is worth it. And this can be removed when we switch to Symfony Routing and Twig.