Some improvement that comes with payum 0.8

* TokenFactoryInterface
* [paypal] return url and cancel url set in payums capture action.

TODO:

* [paypal] reuse notify action that comes with payum. First I have patch payum bundle.

__UPDATE (26.05.14)__

Now the `SyliusPayumBundle` does not load all the services, only if they supported. Also the payum actions (provided by sylius) loaded by container tag (more in PR: https://github.com/Payum/PayumBundle/pull/128). It has to make payum integration to sylius easier.

The tag feature does not work well for be2bill payment. I'll address it later 

Tags gives some advantages: If we add a FooNotifyAction in future for example, users do not have to add it to its config, it will be added automatically, If we rename something, the service for example anything would be broken.