Make a plan for supporting ES 2.0

[sumologic]

Make a plan for supporting ES 2.0

[CCheSumo]

There are a list of breaking changes we would like to roll out in the open source elasticsearch client with the update. Here is the reference page for the 8 changes (issues) and the discussion board for the tasks breakdown (discussion board)
Some of the issues we would like to fix in the current open source client https://github.com/SumoLogic/elasticsearch-client

1. "search_type" -> "scan" is no longer supported #100
2. Use akka-http client instead of spray #84
3. Upgrade akka version to 2.4.14 #90
4. Upgrade scalatest and json4s-native #94
5. Upgrade ES to 5.1 #89
6. Remove ExtendedQueryRoot#80
   7 Remove default value for "highlight" in ElasticJsonDocumen #77
   8 Fix flaky test #72
   9 Remove MultimatchQueryWithOptions and use MultimatchQuery #71
   10 Fix Error in Json format parsing #65
   11 _timestamp depreciated in 5.1

Currently working in progress