allow setting of attributes on the generated routes

[briancappello]

depends on symfony-cmf/routing-auto#21
addresses #139

[dantleech]

Hi, thanks alot for taking the time to do this. I don't like blindly calling setters on unknown objects, we could have added some validation - but then I think letting people call arbitrary methods on objects is a good way to introduce bugs (e.g. you could call setPattern) and also adds more questions - e.g. should we allow token substitution on the attribute values?

But I see the use case, so I did :

symfony-cmf/routing-auto#22

Which I also decided would be a bad idea (basically huge change, for questionable benefit - read the above PR description). I suggest instead that we implement an EventDispatcher which would allow people to set things as they want.

I am closing this, lets continue the discussion in the above issue.