- Implement multiline features as a codec.
- Disable the multiline filter with an error message that tells the user
  to use the codec instead.
Note multiline codec/filter changes
- Fix filter execution for filters that emit multiple events (clone,
  split)
- fix codec initialization
- remove unreleased+deprecated features from filters/base
- deprecate the multiline filter (see the new multiline codec)
- skip date filter tests when we aren't on jruby
- remove debugging