Add a way to get current values/fields from a Recurly_Resource

[iricketson]

In my situation, I'd like to have access to the object values without having to get them one by one. It would be very handy to have a getValues() method (similar to the getErrors() method), that returns the $_values param.

  public function getValues() {
    return $this->_values;
  }

Another idea would be to make the getWriteableAttributes method public, so at least you could programatically iterate through the values that way.

[derekdowling]

+1, this would be extremely nice to have.

[drewish]

#87 has a PR for this, so I'll close it in favor of that.

[drewish]

#87 was merged so this functionality will be available in the next release.