Fixed compatibility with SensioGeneratorBundle 2.5

As from this version, the DialogHelper from the console component is replaced in favor of the new QuestionHelper.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | yes
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #7 

Fixes #7