dropping extending the ContentAwareGenerator class

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | yes
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #34
| License       | MIT
| Depends     | https://github.com/symfony-cmf/Routing/pull/80

according to stof and beberlei, using the request is wrong, we should use the RequestContext instead. that is done in https://github.com/symfony-cmf/Routing/pull/80 - once it is merged we can drop things here.