Some more changes to get global parameters to work

Hey Lincoln,

here is the next pull request. Just minor stuff. But I hope it heads into the right direction.

* bindsTo() is now also implemented. You were correct. I didn't do it a first because I was unsure about the bindings. But it totally makes sense to do it this way.
* For now all the builder methods signatures directly return the builder and not one of the interfaces. I think we can add the interfaces for enforcing correct usage of the fluent API later.
* When calling where() the first time, the code now automatically adds the required binding to add the parameter value to the evaluation context. Not sure if this is the best place.

I think the next steps would be to:
* Find a place to submit the bindings.
* Also enrich the parameters of operations.

The second one should be more or less easy. But I'm unsure how to handle the bindings.