[SPARK-4806] Streaming doc update for 1.2

Important updates to the streaming programming guide
- Make the fault-tolerance properties easier to understand, with information about write ahead logs
- Update the information about deploying the spark streaming app with information about Driver HA
- Update Receiver guide to discuss reliable vs unreliable receivers.

Author: Tathagata Das <tathagata.das1565@gmail.com>
Author: Josh Rosen <joshrosen@databricks.com>
Author: Josh Rosen <rosenville@gmail.com>

Closes #3653 from tdas/streaming-doc-update-1.2 and squashes the following commits:

f53154a [Tathagata Das] Addressed Josh's comments.
ce299e4 [Tathagata Das] Minor update.
ca19078 [Tathagata Das] Minor change
f746951 [Tathagata Das] Mentioned performance problem with WAL
7787209 [Tathagata Das] Merge branch 'streaming-doc-update-1.2' of github.com:tdas/spark into streaming-doc-update-1.2
2184729 [Tathagata Das] Updated Kafka and Flume guides with reliability information.
2f3178c [Tathagata Das] Added more information about writing reliable receivers in the custom receiver guide.
91aa5aa [Tathagata Das] Improved API Docs menu
5707581 [Tathagata Das] Added Pythn API badge
b9c8c24 [Tathagata Das] Merge pull request #26 from JoshRosen/streaming-programming-guide
b8c8382 [Josh Rosen] minor fixes
a4ef126 [Josh Rosen] Restructure parts of the fault-tolerance section to read a bit nicer when skipping over the headings
65f66cd [Josh Rosen] Fix broken link to fault-tolerance semantics section.
f015397 [Josh Rosen] Minor grammar / pluralization fixes.
3019f3a [Josh Rosen] Fix minor Markdown formatting issues
aa8bb87 [Tathagata Das] Small update.
195852c [Tathagata Das] Updated based on Josh's comments, updated receiver reliability and deploying section, and also updated configuration.
17b99fb [Tathagata Das] Merge remote-tracking branch 'apache-github/master' into streaming-doc-update-1.2
a0217c0 [Tathagata Das] Changed Deploying menu layout
67fcffc [Tathagata Das] Added cluster mode + supervise example to submitting application guide.
e45453b [Tathagata Das] Update streaming guide, added deploying section.
192c7a7 [Tathagata Das] Added more info about Python API, and rewrote the checkpointing section.

(cherry picked from commit b004150adb503ddbb54d5cd544e39ad974497c41)
Signed-off-by: Tathagata Das <tathagata.das1565@gmail.com>
[SPARK-4825] [SQL] CTAS fails to resolve when created using saveAsTable

Fix bug when query like:
```
  test("save join to table") {
    val testData = sparkContext.parallelize(1 to 10).map(i => TestData(i, i.toString))
    sql("CREATE TABLE test1 (key INT, value STRING)")
    testData.insertInto("test1")
    sql("CREATE TABLE test2 (key INT, value STRING)")
    testData.insertInto("test2")
    testData.insertInto("test2")
    sql("SELECT COUNT(a.value) FROM test1 a JOIN test2 b ON a.key = b.key").saveAsTable("test")
    checkAnswer(
      table("test"),
      sql("SELECT COUNT(a.value) FROM test1 a JOIN test2 b ON a.key = b.key").collect().toSeq)
  }
```

Author: Cheng Hao <hao.cheng@intel.com>

Closes #3673 from chenghao-intel/spark_4825 and squashes the following commits:

e8cbd56 [Cheng Hao] alternate the pattern matching order for logical plan:CTAS
e004895 [Cheng Hao] fix bug

(cherry picked from commit 0abbff286220bbcbbf28fbd80b8c5bf59ff37ce2)
Signed-off-by: Michael Armbrust <michael@databricks.com>