Complete the hctsa catalog ala comp-engine.org

[sdvillal]

In the online catalog (and computational engine) for hctsa there is some operator metadata that would be worth to bring into python land.

• Feature Categories
• Feature nearest neighbors (I guess over a wide range of time series)
• Explicit code dependencies

From those, nearest neighbors would be the most interesting. Getting up code to assess such information in our own data should be simple and maybe even helpful to assemble feature sets with lower redundancy.