[SPARK-2263][SQL] Support inserting MAP<K, V> to Hive tables

JIRA issue: [SPARK-2263](https://issues.apache.org/jira/browse/SPARK-2263)

Map objects were not converted to Hive types before inserting into Hive tables.

Author: Cheng Lian <lian.cs.zju@gmail.com>

Closes #1205 from liancheng/spark-2263 and squashes the following commits:

c7a4373 [Cheng Lian] Addressed @concretevitamin's comment
784940b [Cheng Lian] SARPK-2263: support inserting MAP<K, V> to Hive tables

(cherry picked from commit 8fade8973e5fc97f781de5344beb66b90bd6e524)
Signed-off-by: Reynold Xin <rxin@apache.org>
[BUGFIX][SQL] Should match java.math.BigDecimal when wnrapping Hive output

The `BigDecimal` branch in `unwrap` matches to `scala.math.BigDecimal` rather than `java.math.BigDecimal`.

Author: Cheng Lian <lian.cs.zju@gmail.com>

Closes #1199 from liancheng/javaBigDecimal and squashes the following commits:

e9bb481 [Cheng Lian] Should match java.math.BigDecimal when wnrapping Hive output

(cherry picked from commit 22036aeb1b2cac7f48cd60afea925b42a5318631)
Signed-off-by: Reynold Xin <rxin@apache.org>
[SPARK-2267] Log exception when TaskResultGetter fails to fetch/deserialze task result

Note that this is only for branch-1.0 because master's been fixed.

Author: Reynold Xin <rxin@apache.org>

Closes #1202 from rxin/SPARK-2267 and squashes the following commits:

ce1b19b [Reynold Xin] [SPARK-2267] Log exception when TaskResultGetter fails to fetch/deserialize task result
Replace doc reference to Shark with Spark SQL.

(cherry picked from commit ac06a85da59db8f2654cdf6601d186348da09c01)
Signed-off-by: Reynold Xin <rxin@apache.org>