[WIP] Twig integration

This pull request is a try to improve the builder by using twig.

**Plan**
- more readable code
- decouple data and views

Future steps could be to improve handling of behaviours.

**Current state:**
*Code*:
Currently I replaced some single methods in the `ObjectBuilder` and the `ExtensionObjectBuilder` with twig templates, but maybe later we can replace the complete `build`-process with rendering the templates.

*Prolems*:
One thing which cause problems is the behaviour filter system: IMO we need to rewrite it, maybe use a dispatcher?

*Tests*:
Currently all tests show green, but the performance is very poor. We can improve this by using twigs own cache system, we just need to set a cache directory.





*References:*
#182