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