replaced debug switches in twig with native supported debug value

There is no need to add an additional debug value for twig. 

The value of kernel.debug (the second argument received by AppKernel) triggers the twig.debug value.
If you want to define the twig debug value than you could do this in the configs with:

    # app/config/config_dev.yml
    twig:
        debug: false

Besides Twig gets `app.debug` as global variable in Symfony. So one could use this value in all used templates.