[SPARK-10496][SQL] Add DataFrame cumulative sum

[zhengruifeng]

What changes were proposed in this pull request?

Add DataFrame cumulative sum.
Given numeric columns, create new columns which are the cumulative sum.

How was this patch tested?

unit tests and manual tests

[rxin]

Thanks for contributing, but isn't this similar to just window function?

[SparkQA]

Test build #56551 has finished for PR 12578 at commit 97af903.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[zhengruifeng]

@rxin It is said in JIRA that window function is not efficient for a large number of rows in this problem. @jkbradley

[SparkQA]

Test build #66499 has finished for PR 12578 at commit 97af903.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[rxin]

I'm going to move the discussions over to JIRA.

[zhengruifeng]

This PR is out of date, I think it's time to close it.