SPARK-1509: add zipWithIndex zipWithUniqueId methods to java api

Author: witgo <witgo@qq.com>

Closes #423 from witgo/zipWithIndex and squashes the following commits:

039ec04 [witgo] Merge branch 'master' of https://github.com/apache/spark into zipWithIndex
24d74c9 [witgo] review commit
763a5e4 [witgo] Merge branch 'master' of https://github.com/apache/spark into zipWithIndex
59747d1 [witgo] review commit
7bf4d06 [witgo] Merge branch 'master' of https://github.com/apache/spark into zipWithIndex
daa8f84 [witgo] review commit
4070613 [witgo] Merge branch 'master' of https://github.com/apache/spark into zipWithIndex
18e6c97 [witgo] java api zipWithIndex test
11e2e7f [witgo] add zipWithIndex zipWithUniqueId methods to java api