instead of expecting a list manage the update batch as a stack on which we are happening the values in order.

now supports batch via HTTP.

A batch is a JSON seent on Post with following headers and similar body:

Headers :

x-barrel-write-batch: true
x-barrel-async: false

JSON:

{ "updated":
  [
     { "op": "put", "doc": {},  "rev": "" },
     { "op": "delete", "id": "someid", "rev": "" },
     { "op": "post", "doc": {} }
  ]
}

Response is the following

if Async is true:

{ "ok" : true }

Or following response

{
   "ok": true,
   "results":
      [
        {"status": "ok", "id": "docid", "rev": "revid" },
        ..
     ]
 }

Results can be

-  {"status": "ok", "id": "docid", "rev": "revid" }
-  {"status": "error", "reason": "not found" }
-  {"status": "conflict", "reason": "doc exists" }
-  {"status": "conflict", "reason": "revision conflic" }

helper to write batches so the HTTP API don't rely on barrel_db. While I'm here, move the json parsing to the batch module.

The batch API also supports attachments.