Tasks for Version 0.2

[bitsofbits]

• Use segment IDs to drop short segments Use Segment ID to drop short segments #106

• make Compute metrics tracks unclassified, active vessels correctly.

• Clean up source lists so that detailed class always present when available,
  coarser classes when not.

• Switch to multihot.

• Begin using subset of training data for training evaluation; model selection, etc.

  • reusable holdout?

• Model bakeoff use 5x cross validation.
  - Swap current test/training because we've looked at test a lot already.