- Compile capture processing to ruby code to avoid asking questions

  about startup-time configuration every time there's an event.

  This has a measured 6.3x perf improvement in grok filter performance.

  It passes *almost* all the tests (66 examples, 4 failures). Each
  failure is related to what I think is an uncommon edge case or
  a feature that is going away eventually. The broken tests will be
  fixed eventually.