Spec for HAPROXYHTTP pattern.

We ran into parsing problems with this pattern and my first step was to
look at the tests. There were none so I took the apache log example and
adapted it for haproxy using the haproxy documentation format as the
example log string.

HELP! I am not sure why using date { timestamp =>
"dd/MMM/YYYY:HH:mm:ss.S" } doesn't set the event timestamp correctly so
the example uses mutate but at least passes.
Use date filter to set the timestamp from the haproxy accept_date
Remove date filter from haproxy parsing example.
LOGSTASH-1106 Adding additional file output path option documentation. This is to highlight functionality of the path option that was not previously documented, and to prevent additional pull requests for implementation of date-based log rotation.
unix input: remove socket in case of EADDRINUSE
wrap resolve/reverse actions in timeouts
Update HOSTNAME in grok-patterns

RFC952 states of a hostname: "The last character must not be a minus sign or period."
https://tools.ietf.org/html/rfc952

Some of the limitations in RFC952 were lifted by RFC1123, but not this one.
https://tools.ietf.org/html/rfc1123

The updated regex still allows single character hostnames, but does not allow the final character in any section to be a '-'.
added set metric output
bumped statsd-ruby to version 1.2.0 to support set metrics
Added configs for Datadog metrics.
Filter to merge multiline rails logs using UUID
Filter to merge multiline rails logs using UUID
Europe date metric compliance is dd/mm/yyyy
Not all irc messages have a user / nickname

Blows up with:

Restarting input due to exception {:plugin=><LogStash::Inputs::Irc
    nick=>"logstash_fr", channels=>["#fr"], charset=>"UTF-8",
        host=>"localhost", type=>"irc", user=>"logstash",
        real=>"logstash">, :level=>:error}
        Input thread exception {:plugin=><LogStash::Inputs::Irc
            nick=>"logstash_infra", channels=>["#infra"],
                charset=>"UTF-8", host=>"localhost", type=>"irc",
                user=>"logstash", real=>"logstash">,
                :exception=>#<NoMethodError: undefined method `nick' for
                    nil:NilClass>,
                :backtrace=>["file:/opt/logstash-monolithic.jar!/logstash/inputs/irc.rb:77:in
                    `run'", "org/jruby/RubyKernel.java:1409:in `loop'",
                "file:/opt/logstash-monolithic.jar!/logstash/inputs/irc.rb:73:in
                    `run'",
                "file:/opt/logstash-monolithic.jar!/logstash/agent.rb:761:in
                    `run_input'",
                "file:/opt/logstash-monolithic.jar!/logstash/agent.rb:407:in
                    `start_input'"], :level=>:warn}
Added batching to sqs output
Merge branch 'master' of https://github.com/logstash/logstash
added validation of SQS batch_events config parameter
Parse and batch incoming metrics.
Added SQS Sent Timestamp support
Merge branch 'master' of https://github.com/logstash/logstash