[SPARK-1981][Streaming][Hotfix] Fixed docs related to kinesis

- Include kinesis in the unidocs
- Hide non-public classes from docs

Author: Tathagata Das <tathagata.das1565@gmail.com>

Closes #2239 from tdas/kinesis-doc-fix and squashes the following commits:

156e20c [Tathagata Das] More fixes, based on PR comments.
e9a6c01 [Tathagata Das] Fixed docs related to kinesis