SPARK-4445, Don't display storage level in toDebugString unless RDD is persisted.

Author: Prashant Sharma <prashant.s@imaginea.com>

Closes #3310 from ScrapCodes/SPARK-4445/rddDebugStringFix and squashes the following commits:

4e57c52 [Prashant Sharma] SPARK-4445, Don't display storage level in toDebugString unless RDD is persisted
SPARK-2811 upgrade algebird to 0.8.1

Author: Adam Pingel <adam@axle-lang.org>

Closes #3282 from adampingel/master and squashes the following commits:

70c8d3c [Adam Pingel] relocate the algebird example back to example/src
7a9d8be [Adam Pingel] SPARK-2811 upgrade algebird to 0.8.1
[SPARK-4444] Drop VD type parameter from EdgeRDD

Due to vertex attribute caching, EdgeRDD previously took two type parameters: ED and VD. However, this is an implementation detail that should not be exposed in the interface, so this PR drops the VD type parameter.

This requires removing the `filter` method from the EdgeRDD interface, because it depends on vertex attribute caching.

Author: Ankur Dave <ankurdave@gmail.com>

Closes #3303 from ankurdave/edgerdd-drop-tparam and squashes the following commits:

38dca9b [Ankur Dave] Leave EdgeRDD.fromEdges public
fafeb51 [Ankur Dave] Drop VD type parameter from EdgeRDD
Revert "[SPARK-4075] [Deploy] Jar url validation is not enough for Jar file"

This reverts commit 098f83c7ccd7dad9f9228596da69fe5f55711a52.
[DOCS][SQL] Fix broken link to Row class scaladoc

Author: Andy Konwinski <andykonwinski@gmail.com>

Closes #3323 from andyk/patch-2 and squashes the following commits:

4699fdc [Andy Konwinski] Fix broken link to Row class scaladoc