[SPARK-1504], [SPARK-1505], [SPARK-1558] Updated Spark Streaming guide

- SPARK-1558: Updated custom receiver guide to match it with the new API
- SPARK-1504: Added deployment and monitoring subsection to streaming
- SPARK-1505: Added migration guide for migrating from 0.9.x and below to Spark 1.0
- Updated various Java streaming examples to use JavaReceiverInputDStream to highlight the API change.
- Removed the requirement for cleaner ttl from streaming guide

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

Closes #652 from tdas/doc-fix and squashes the following commits:

cb4f4b7 [Tathagata Das] Possible fix for flaky graceful shutdown test.
ab71f7f [Tathagata Das] Merge remote-tracking branch 'apache-github/master' into doc-fix
8d6ff9b [Tathagata Das] Addded migration guide to Spark Streaming.
7d171df [Tathagata Das] Added reference to JavaReceiverInputStream in examples and streaming guide.
49edd7c [Tathagata Das] Change java doc links to use Java docs.
11528d7 [Tathagata Das] Updated links on index page.
ff80970 [Tathagata Das] More updates to streaming guide.
4dc42e9 [Tathagata Das] Added monitoring and other documentation in the streaming guide.
14c6564 [Tathagata Das] Updated custom receiver guide.
make master support multiple executors per worker
doc update