[SPARK-6227][MLLIB][PYSPARK] Implement PySpark wrappers for SVD and PCA (v2)

[MLnick]

Add PCA and SVD to PySpark's wrappers for RowMatrix and IndexedRowMatrix (SVD only).

Based on #7963, updated.

How was this patch tested?

New doc tests and unit tests. Ran all examples locally.

[MLnick]

Based on @MechCoder's work in #7963.

cc @holdenk@dusenberrymw

[SparkQA]

Test build #75741 has finished for PR 17621 at commit 3ba2411.

• This patch fails Python style tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #75742 has finished for PR 17621 at commit 3ea88e2.

• This patch fails Python style tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #75743 has finished for PR 17621 at commit 0118f2c.

• This patch fails PySpark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #75744 has finished for PR 17621 at commit 56205d2.

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

[holdenk]

Thanks for reviving this @MLnick :)

[dusenberrymw]

Yeah, great to see this being finished up, @MLnick. LGTM.

[MechCoder]

Thanks @MLnick !

[SparkQA]

Test build #76101 has finished for PR 17621 at commit 07808fc.

• This patch fails Python style tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #76102 has finished for PR 17621 at commit 94006a4.

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

[MLnick]

If no further comments I'll merge this into branch-2.2 within a few days.

[MLnick]

Jenkins retest this please

[SparkQA]

Test build #76377 has finished for PR 17621 at commit 94006a4.

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

[holdenk]

LGTM

[MLnick]

Merged to master/branch-2.2. Thanks again for the original work @MechCoder!

[SixAlien3]

@MLnick Hi, I'm interesting in this PySpark wrapper for SVD. How many columns can this support? Cuz I see in the old document it can only support columns <1000. How about this wrapper?