Implement checks for preprocessing (and run if missing) for each pipeline

[Pierson Browne]

Currently, it's necessary to run nate.preprocess to get the spaCy data necessary to instantiate a nate pipeline.

First, pipelines should elegantly check to see if the necessary preprocessing has been completed. This should be simple and is a logical endpoint.

For further user friendliness, though, it would be prudent to enable each of the pipeline-returning functions to also run preprocessing using defaults that will configure the preprocess function to meet their requirements.

Low priority.