Add support for _bulk endpoint in 'Any Request'

[maximpashuk]

Any _bulk request to elasticsearch requires a request body which is not single JSON object, but a multiple JSON objects splitted by newline.

http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/docs-bulk.html#docs-bulk

{ "index" : { "_index" : "test", "_type" : "type1", "_id" : "1" } }
{ "field1" : "value1" }
{ "delete" : { "_index" : "test", "_type" : "type1", "_id" : "2" } }
{ "create" : { "_index" : "test", "_type" : "type1", "_id" : "3" } }
{ "field1" : "value3" }
{ "update" : {"_id" : "1", "_type" : "type1", "_index" : "index1"} }
{ "doc" : {"field2" : "value2"} }

For now elasticsearch-head does not allow such requests using 'Any Request' tab - JSON validation error occurs.
Please add ability to send _bulk requests using 'Any Request' tab.

[csucjh]

This problem needs to be solved urgently