[SPARK-4062][Streaming]Add ReliableKafkaReceiver in Spark Streaming Kafka connector

Add ReliableKafkaReceiver in Kafka connector to prevent data loss if WAL in Spark Streaming is enabled. Details and design doc can be seen in [SPARK-4062](https://issues.apache.org/jira/browse/SPARK-4062).

Author: jerryshao <saisai.shao@intel.com>
Author: Tathagata Das <tathagata.das1565@gmail.com>
Author: Saisai Shao <saisai.shao@intel.com>

Closes #2991 from jerryshao/kafka-refactor and squashes the following commits:

5461f1c [Saisai Shao] Merge pull request #8 from tdas/kafka-refactor3
eae4ad6 [Tathagata Das] Refectored KafkaStreamSuiteBased to eliminate KafkaTestUtils and made Java more robust.
fab14c7 [Tathagata Das] minor update.
149948b [Tathagata Das] Fixed mistake
14630aa [Tathagata Das] Minor updates.
d9a452c [Tathagata Das] Minor updates.
ec2e95e [Tathagata Das] Removed the receiver's locks and essentially reverted to Saisai's original design.
2a20a01 [jerryshao] Address some comments
9f636b3 [Saisai Shao] Merge pull request #5 from tdas/kafka-refactor
b2b2f84 [Tathagata Das] Refactored Kafka receiver logic and Kafka testsuites
e501b3c [jerryshao] Add Mima excludes
b798535 [jerryshao] Fix the missed issue
e5e21c1 [jerryshao] Change to while loop
ea873e4 [jerryshao] Further address the comments
98f3d07 [jerryshao] Fix comment style
4854ee9 [jerryshao] Address all the comments
96c7a1d [jerryshao] Update the ReliableKafkaReceiver unit test
8135d31 [jerryshao] Fix flaky test
a949741 [jerryshao] Address the comments
16bfe78 [jerryshao] Change the ordering of imports
0894aef [jerryshao] Add some comments
77c3e50 [jerryshao] Code refactor and add some unit tests
dd9aeeb [jerryshao] Initial commit for reliable Kafka receiver
[SPARK-4390][SQL] Handle NaN cast to decimal correctly

Author: Michael Armbrust <michael@databricks.com>

Closes #3256 from marmbrus/NanDecimal and squashes the following commits:

4c3ba46 [Michael Armbrust] fix style
d360f83 [Michael Armbrust] Handle NaN cast to decimal
[SPARK-4391][SQL] Configure parquet filters using SQLConf

This is more uniform with the rest of SQL configuration and allows it to be turned on and off without restarting the SparkContext.  In this PR I also turn off filter pushdown by default due to a number of outstanding issues (in particular SPARK-4258).  When those are fixed we should turn it back on by default.

Author: Michael Armbrust <michael@databricks.com>

Closes #3258 from marmbrus/parquetFilters and squashes the following commits:

5655bfe [Michael Armbrust] Remove extra line.
15e9a98 [Michael Armbrust] Enable filters for tests
75afd39 [Michael Armbrust] Fix comments
78fa02d [Michael Armbrust] off by default
e7f9e16 [Michael Armbrust] First draft of correctly configuring parquet filter pushdown
[SQL] Minor cleanup of comments, errors and override.

Author: Michael Armbrust <michael@databricks.com>

Closes #3257 from marmbrus/minorCleanup and squashes the following commits:

d8b5abc [Michael Armbrust] Use interpolation.
2fdf903 [Michael Armbrust] Better error message when coalesce can't be resolved.
f9fa6cf [Michael Armbrust] Methods in a final class do not also need to be final, use override.
199fd98 [Michael Armbrust] Fix typo
[SQL] Don't shuffle code generated rows

When sort based shuffle and code gen are on we were trying to ship the code generated rows during a shuffle.  This doesn't work because the classes don't exist on the other side.  Instead we now copy into a generic row before shipping.

Author: Michael Armbrust <michael@databricks.com>

Closes #3263 from marmbrus/aggCodeGen and squashes the following commits:

f6ba8cf [Michael Armbrust] fix and test