Replaced the multi-field type in favour for the multi fields option that can be set on any core field.

When upgrading to ES 1.0 the existing mappings with a multi-field type automatically get replaced to a core field with the new `fields` option.

If a `multi_field` type-ed field doesn't have a main / default field, a default field will be chosen for the multi fields syntax. The new main field type
will be equal to the first `multi_field` fields' field or type string if no fields have been configured for the `multi_field` field and in both cases
the default index will not be indexed (`index=no` is set on the default field).

If a `multi_field` typed field has a default field, that field will replace the `multi_field` typed field.

Closes to #4521
Add new option `min_doc_count` to terms and histogram aggregations.

`min_doc_count` is the minimum number of hits that a term or histogram key
should match in order to appear in the response.

`min_doc_count=0` replaces `compute_empty_buckets` for histograms and will
behave exactly like facets' `all_terms=true` for terms aggregations.

Close #4662
Fix YAML in test/indices.open/20_multiple_indices.yaml
Default stopwords list should be `_none_` for all but language-specific analyzers

`standard_html_strip` and `pattern` analyzer support stopwords which are
set to the default `english` stopwords by default. Those analyzers
should not use stopwords by default since they are language neutral

Closes #4699
Fixing up code block delimeters for asciidoctor

You can now successfully run the docs through asciidoctor
Rename RobinEngine and friends to InternalEngine

Closes #4633
Added test with awaits annotation that exposes a merge mapping issue.

 If the path_type is set to `just_name` in a multi_field typed field and that field is updated (for example another multi field is added) then if the path isn't specified again the path_type isn't taken into account and full path names are generated.
Remove ancient `engine.robin.refresh_interval`

Closes #4706
Support sibling columns, with _cat/indices?pri as first go.

% curl localhost:9200/_cat/indices\?h=health,index,rep,docs.count,ss,cs,fm\&v\&pri
health index   rep docs.count      ss  pri.ss cs pri.cs     fm pri.fm
green  wiki      1       6401 302.9mb 151.4mb 0b     0b 25.1mb     0b
green  twitter   1      11434    64mb    32mb 0b     0b     0b     0b

Closes #4689.
CompletionFieldMapper.Builder should make a copy of the default FieldType and set the builder field.
Check if entry value can be cast to a Map, if not fail with a better error.
remove System.out.println
[SPEC] Updated cluster.node_stats and indices.stats
Standardized use of “*_length” for parameter names rather than “*_len”.
Java Builder apis drop old “len” methods in favour of new “length”
Rest APIs support both old “len: and new “length” forms using new ParseField class to a) provide compiler-checked consistency between Builder and Parser classes and
b) a common means of handling deprecated syntax in the DSL.
Documentation and rest specs only document the new “*length” forms
Closes #4083
[TEST] Updated cluster.node_stats test
Add missing #setBreaker setter to NodesStatsRequestBuilder
Encapsulate Operations on SegmentReader in a utils class

This commit adds support to extract SegmentReader instances from
FilteredAtomicReader instances to support reader wrapping in
caches as well.
Fix RandomExceptionCircuitBreakerTests

RandomExceptionCircuitBreakerTests never actually installed
the FilteredAtomicReader that should throw random exceptions
when field data is loaded.
Add better error reporting if a json spec can not be parsed
Add missing closing '}' to indices.stats.json