Changed the default of SourceFieldMapper's includes & excludes to be null, to support a "not specified" state, which is important now that they are update-able & merge-able
Thread Pool: Remove blocking type option
The blocking thread pool type is not recommended to be used, since it will end up blocking the IO thread most times when executing, which is not recommended (other operations will then stall as well).
closes #3531
increase (use default) timeout to green in test
added a top level try catch for threaded operations. Exception which bubbled up could cause requests to hang.
Switched all catch (Exception e) to catch (Throwable e)
use the now publicly available getDisjuncts
GetMapping failed when index had no mapping (yet)

Closes #3534
Change response format of term vector endpoint

This commit changes the response format of the term vectors
to be consistent with the response format of the analyze endpoint.

```
{
   "_index": "test",
   "_type": "type1",
   "_id": "1",
   "_version": 1,
   "exists": true,
   "term_vectors": {
      "field_with_positions_offsets": {
         "field_statistics": {..},
         "terms": {
            "evil": {
               "term_freq": 2,
               "pos": [ 4 , 7 ],
               "start": [ 17, 40 ],
               "end": [ 21 , 44 ]
            },
            "orthodontist": {
               "term_freq": 1,
               "pos": [ 5 ]
               ],
               "start": [ 22 ],
               "end": [ 34]
            }
         }
      }
   }
}
```

becomes

```
{
   "_index": "test",
   "_type": "type1",
   "_id": "1",
   "_version": 1,
   "exists": true,
   "term_vectors": {
      "field_with_positions_offsets": {
         "field_statistics": {..},
         "terms": {
            "evil": {
               "term_freq": 2,
               "tokens": [
                   { "position": 4, "start_offset": 17, "end_offset" : 21 },
                   { "position": 7, "start_offset": 40, "end_offset" : 44 }
               ]
            },
            "orthodontist": {
               "term_freq": 1,
               "tokens" : [ { "position": 5 , "start_offset" : 22, "end_offset" : 34 } ]
            }
         }
      }
   }
}
```

Closes issue #3484
Fix search shards count method when targeting concrete and routing-aliased indices
Added test for #3268 and comments to test for #2682
XContentHelper.mergeDefaults with single key object list ([ { key: .. } , {key : ... } .. ] ) didn't add defaults which were not already in content

 Closes #3538
Improved multi percolate api, to bundle all the requests by shard into one shard level request instead of sending each percolate request separately to the shards.