Metric: syntax trees

[drusepth]

It'd be suuuuper cool if we could break text down into syntax trees. Might need a grammar for the english language; not sure if that exists freely yet.

Also, not sure how to expose this in text over the API, but just a JSON representation of the tree would probably be fine.

Having syntax trees could open up discourse analysis, semantic analysis, and rhetorical analysis.

[drusepth]

Data for this now exists in IntentService#RelationExtraction. Needs to be drawn into a pretty tree still.