[SPARK-2076][SQL] Pushdown the join filter & predication for outer join

As the rule described in https://cwiki.apache.org/confluence/display/Hive/OuterJoinBehavior, we can optimize the SQL Join by pushing down the Join predicate and Where predicate.

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

Closes #1015 from chenghao-intel/join_predicate_push_down and squashes the following commits:

10feff9 [Cheng Hao] fix bug of changing the join type in PredicatePushDownThroughJoin
44c6700 [Cheng Hao] Add logical to support pushdown the join filter
0bce426 [Cheng Hao] Pushdown the join filter & predicate for outer join

(cherry picked from commit db0c038a66cb228bcb62a5607cd0ed013d0f9f20)
Signed-off-by: Michael Armbrust <michael@databricks.com>