added failing tests and made them succeed for issue #732
renamed .Object(T) in favor of .Id(T), improved naming on Update() and Bulk(Update()) and made them consistent
Renamed Id(T) to IdFrom(T), PartialDocument() to Doc() and PartialDocumentAsUpsert() to DocAsUpsert()
Merge pull request #795 from elasticsearch/fix/streamline-updates

Try to streamline the update api's