Add check-netstat-tcp.rb, heavily based on metrics-netstat-tcp.rb
opsgenie heartbeat: use apiKey and (new!) source config
consistently use '...'
check-netstat-tcp.rb fixes since it's a check not a metric
adding gluster/gluster-georepl-status.rb

- plugin to check if Gluster's geo-replication is healthy or not.
added flag to pass states
bugfix: requires sudo
renamed check and made it executable
added more exclusions
fix json syntax in plugin example configs
add ipv6 support to check-netstat-tcp.rb
Change message format handed to Logstash.

Matches https://logstash.jira.com/browse/LOGSTASH-675
check-sftp - Added new file count and aging checks
Type is not mandatory for Logstash's schema v1.
Oops.
check messages in individual queue
Add some documentation to commandline parameters
Checks for ElasticSearch 0.9x and 1.x

/_cluster/nodes/_local has been retired with ES 1.0, so this check does
not work anymore.
By identifying the cluster version before running the check,
we can adjust the URL.
Add docker/check-docker-containers.rb
Modified description and script name