Use Forwardable in Rest class to delegate API.

[rdvdijk]

This finalizes all the Rest class refactoring. All argument defaults that were in left have been moved into the separate classes. There is hardly any logic left in the Rest class, and all API requests are delegated directly to the new classes.

[rdvdijk]

Whoops! Failing tests?.. let me fix that.

Update: I am getting failing tests now myself, but not those that Travis reports..

Very strange, the status seems to be missing from the batch request:

  1) Neography::Rest simple batch can delete a single relationship
     Failure/Error: batch_result[0]["status"].should == 201
       expected: 201
            got: nil (using ==)
     # ./spec/integration/rest_batch_spec.rb:152:in `block (3 levels) in <top (required)>'

  2) Neography::Rest referenced batch can create a relationship from a unique node
     Failure/Error: batch_result.should_not be_nil
       expected: not nil
            got: nil
     # ./spec/integration/rest_batch_spec.rb:432:in `block (3 levels) in <top (required)>'

[rdvdijk]

I'm not sure what happened, but I cannot reproduce the errors anymore.. (weird?)

[maxdemarzi]

Let's merge and see if it is just a fluke...