Update to use most recent `grape` functions

[caufieldjh]

• [x] Update run_classifier to use new grape methods
• [ ] Remove obsoleted methods
• [ ] Update tests and test fixtures
• [ ] Include list of valid embedder and classifier names

[caufieldjh]

I've been trying out configs with newer grape embedding methods but keep getting

NotImplementedError: None isn't implemented yet

suggesting that I'm just providing the wrong name, but I've run out of variations to try. This should be documented anyway.

(This error is actually being thrown when the classifier model isn't recognized, though I'm just using Perceptron)