fix encode (output) for oldlogstashjson codec.

It was referencing the obj variable which didn't exist
[elasticsearch_river][Fix] use mq.publish_serialized instead of receive_raw

receive_raw is no longer available in RabbitMQ.

elasticsearch_river throw the exception "undefined method `receive_raw'"

This commit fix issues 1298 and 1384
Write a failing test when prefix & include/exclude keys are used together
Fix a bug where field goes missing if include/exclude is used with prefix
Update grok-patterns

Add LOGLEVEL pattern "ALERT"
Fixes LOGSTASH-1328
Make 'if "something" not in [nonexistent] { ... }' succeed

My argument is checking for the absence of a value in a field that doesn't
exist should return true, currently it is false.

This fixes the case where an event which has never been tagged now works with
this logic:

    grok {
      ...
    }
    if "_grokparsefailure" not in [tags] {
      ...
    }
Fix fail() invocation if no config file is given.
Small enhancements to netflow codec

- Add configurable target field for netflow fields, defaults to "netflow"
- Add configurable filter to restrict which versions to accept
Stick to rufus-scheduler 2.0.x versions.

Unbreaks tests as seen in
https://travis-ci.org/logstash/logstash/jobs/12047597.
Make ES index requests synchronous. Prior to this, I had incorrectly
assumed that elasticsearch acting as a client had a fixed-size thread
pool to limit the number of active bulk index requests. This now
executes bulk index requests one at a time.
Unbreak #to_epoch method in datadog output plugin. (LOGSTASH-1427)

The event timestamp might already be a Time object.
Use latest kibana for the flatjar. (LOGSTASH-1416)
Merge pull request #678 from jippi/patch-1

Fixes LOGSTASH-1328
Merge pull request #688 from logstash/synchronous-elasticsearch

Make ES index requests synchronous. Prior to this, I had incorrectly
rollback #678 it turns out this is really a bug in the ftw gem.
version bump ftw gem
Merge pull request #695 from logstash/es_http-fix

Fix for elasticsearch_http output
Merge pull request #687 from bernd/rufus-scheduler-version

Stick to rufus-scheduler 2.0.x versions
- Add more tests to verify document index and index type settings