Changed common terms query to also support camelCased parameters
and renamed disable_coords to disable_coord, to be consistent with
the bool query

Closes #3074
Fix bug in DateFieldMapper where format is serialized instead of locale

This fix adds a default serialization step in the SimpleDateMappingTests
that parses the mapping, builds the mapper, serializes the mapper and
rebuilds the actual mapper from the serialization result. The contained
information must be equivalent to the original mapping.

The fixed bug has no issue assigned to is since the code is unreleased yet.
Added three new index alias related apis.

Added apis to get specific index aliases based on filtering by alias name and index name:
```
curl -XGET 'localhost:9200/{index_or_alias}/_alias/{alias_name}'
```

Added delete index alias api for deleting a single index alias:
```
curl -XDELETE 'localhost:9200/{index}/_alias/{alias_name}'
```

Added create index alias api for adding a single index alias:
```
curl -XPUT 'localhost:9200/{index}/_alias/{alias_name}'

curl -XPUT 'localhost:9200/{index}/_alias/{alias_name}' -d '{
	"routing" : {routing},
	"filter" : {filter}
}'

```

Closes #3075 #3076 #3077
Fix String.format to use Locale.ROOT
Added testcase to ensure #3078 doesn't fail
wait for green/yellow status
Never throw an IAE if the IndexMapper isn't present in PostingsFormat

If we throw an exception in the PostingsFormat during a merge we essentially
fail the entire merge which can lead to a corrupt index. We should rather
return the default postings format for the new segment and log a warning.

Closes #3088
Iter 1.
Iter 2.