update docs to reflect how default write consistency with 1 replica behaves
Docs: tidied configuration.asciidoc
Update stemmer-override-tokenfilter.asciidoc
percolator: fix handling of nested documents

Nested documents were indexed as separate documents, but it was never checked
if the hits represent nested documents or not. Therefore, nested objects could
match not nested queries and nested queries could also match not nested documents.

Examples are in issue #6540 .

closes #6540
closes #6544
Aggregations: Added percentile rank aggregation

Percentile Rank Aggregation is the reverse of the Percetiles aggregation.  It determines the percentile rank (the proportion of values less than a given value) of the provided array of values.

Closes #6386
[TEST] Disable automatic refresh to prevent unintended field data warming of the the _parent field.
[TEST] Only use the clients from the node.
Also send Refresh and Flush actions to relocation targets

Currently we send relocation & flush actions based on all assigned ShardRoutings. During the final stage of relocation, we may miss to refresh/flush a shard if the coordinating node has not yet processed the cluster state update indicating that a relocation is completed *and* the relocation target node has already processed it (i.e., started the shard and has accepted new indexing requests).

Closes #6545
Fixed typo in TransportAction log line
[TEST] Remove indentation on indices.stats test setups

The new indices.stats tests have the setup section indented, which
can cause problems for some yaml parsers.
significant terms: fix json response

Commit fbd7c9aa5d6c1c introduced a regression that caused
the min_doc_count to be equal to the number of documents in the
background set. As a result no buckets were built when the
response for significant terms was created.
This only affected the final XContent response.

closes #6535
[DOCS] Fixed json example in nested-aggregation.asciidoc
REST API: Allow to configure JSONP/callback support

Added the http.jsonp.enable option to configure disabling of JSONP responses, as those
might pose a security risk, and can be disabled if unused.

This also fixes bugs in NettyHttpChannel
* JSONP responses were never setting application/javascript as the content-type
* The content-type and content-length headers were being overwritten even if they were set before

Closes #6164
Mapping: Fix possibility of losing meta configuration on field mapping update

The TTL, size, timestamp and index meta properties could be lost on an
update of a single field mapping due to a wrong comparison in the
merge method (which was caused by a wrong initialization, which marked
an update as explicitely disabled instead of unset.

Closes #5053
Java API: BulkRequest#add(Iterable) to support UpdateRequests

Closes #6551
[TEST] Added (trace) logging to testGetFields_complexField
Mappings: Allow _version to use `disk` as a doc values format.

VersionFieldMapper.defaultDocValuesFormat claims that the default is `disk`.
This is not used to choose the DV format in the index but for mappings
serialization in order to know when the _version doc values format is
different from the default format. This made it impossible to use the `disk`
doc values format since mappings would never retain that information at
serialization time.

Close #6523
Index field names of documents.

The `exists` and `missing` filters need to merge postings lists of all existing
terms, which can be very costly, especially on high-cardinality fields. This
commit indexes the field names of a document under `_field_names` and reuses it
to speed up the `exists` and `missing` filters.

This is only enabled for indices that are created on or after Elasticsearch
1.3.0.

Close #5659
Fielddata: Merge ordinals APIs into BytesValues.WithOrdinals.

Mid-term we should switch from `BytesValues` to Lucene's doc values APIs, in
particular the `SortedSetDocValues` class. While `BytesValues.WithOrdinals` and
SortedSetDocValues expose the same functionality, `BytesValues.WithOrdinals`
exposes its ordinals via a different `Ordinals.Docs` object while
`SortedSetDocValues` exposes them on the same object as the one that holds the
values. This commit merges ordinals into `BytesValues.WithOrdinals` in order to
make both classes even closer.

Global ordinals were a bit tricky to migrate so I just changed them to use
Lucene's OrdinalMap that will soon (LUCENE-5767, scheduled for 4.9) have the
same optimizations as our global ordinals.

Close #6524
Fielddata: Move `getTermsEnum` from `AtomicFieldData` to `BytesValues.WithOrdinals`.

Similarly to `SortedSetDocValues.termsEnum()`.

Relates to #6524