Added some exceptions to the method order in CS

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | n/a

See https://github.com/silexphp/Silex/pull/936#issuecomment-40591230 for the reason. Formalizing this case in the doc is a good idea IMO.