Add slope and metric group for ganglia output.
Catch systemexit from kibana
- add tests for drop filter
- promote drop filter to milestone 3
- restore 'type' 'tags' and 'add_field' feature that was lost during the
  Great Codec Migration ;)
- fix docs
- add a tag for events that have multiple lines (keeps backwards compat
to the older multiline filter)
- add tests to cover this behavior.
- standardize of a few field names:
  * host: the origin of the event (for file input, etc, many times this is
    obvious. For network inputs, this is often the client ip address)
  * path: the origin path of the event (file path, EventLog source, etc)
- some misc style cleanup done while doing the above.
- remove unnecessary thread name settings (the pipeline does this now)
Add missing decorate() calls to inputs.
Merge pull request #608 from bernd/add-missing-event-decoration

Add missing decorate() calls to inputs
- add 'deps' command only to bin/logstash for downloading any
  necessary dependencies.
Update docs on dev/usage
- remove 'source' fields (a relic of the old @source field which is gone
now)
Fix syntax
Update to reflect 1.2
Update links for configuration details
fix ordering
- use milestones
- use event[...] now
- fix references to event.message (now is event["message"])
- update old references to event.tags, event.unix_timestamp, and
event.ruby_timestamp