Added the possiblity to use dinamyc templates.

 For example: 

	elasticsearch {
                        cluster => "logstash"
                        index => "%{type}-logstash-%{+YYYY.MM.dd}"
                        template => "/etc/logstash/conf.d/%{type}-template.json"
                        template_name => "%{type}"
        }
It will also allow to parametrize the template. For example:

{
  "template" : "%{client_id}-*",
  "settings" : {
    "number_of_shards"            : 5,
    "index.cache.field.type"      : "soft",
    "index.refresh_interval"      : "2s",
    "index.store.compress.stored" : true,
    "index.query.default_field"   : "@message"
  },
  ......
}
please remove trailing whitespace