implementing Index Status API for issue #299

Added ElasticClient-Status with methods to retrieve status
Added StatusParams to allow query string property setting
Added StatusResponse and child Stat objects to deserialize response
Added Status API tests to Nest.Tests.Integration project
Adding documentation for Status API
Adding support for shard_size to TermFacetDescriptor issue #423
Merge pull request #1 from richclement/feature-branch

Adding support for shard_size to TermFacetDescriptor issue #423
Merge pull request #425 from richclement/master

implementing Index Status API for issue #299