Updated json output to allow for display of worker state

Ops teams need to ensure that the cluster is functional and performant.  Having to scrape the html source for worker state won't work reliably, and will be slow.  By exposing the state in the json output, ops teams are able to ensure a fully functional environment by querying for the json output and parsing for dead nodes.
Merge pull request #834 from Daemoen/master

Updated json output to allow for display of worker state
Revert "Merge pull request #834 from Daemoen/master"

This reverts commit 230ab2722ebd399afcf64c1a131f4929f602177d, reversing
changes made to 659553b21ddd7504889ce113a816c1db4a73f167.
Use the JSON formatter from Scala library and removed dependency on lift-json.

It made the JSON creation slightly more complicated, but reduces one external dependency. The scala library also properly escape "/" (which lift-json doesn't).
fixing typo
Merge pull request #843 from Reinvigorate/bug-879

fixing typo in conf/slaves
Merge pull request #841 from rxin/json

Use the JSON formatter from Scala library and removed dependency on lift-json.
Reversing the argument order in zipPartitions to enable stronger type inference.
Merge pull request #839 from jegonzal/zip_partitions

Currying RDD.zipPartitions
Removed the unused shuffleId in ShuffleDependency's constructor.
Removed the mapSideCombine option in CoGroupedRDD.
Removed the mapSideCombine option in partitionBy.
Moved shuffle serializer setting from a constructor parameter to a setSerializer method in various RDDs that involve shuffle operations.
Merge pull request #846 from rxin/rdd

Two minor RDD refactoring
Merge pull request #840 from AndreSchumacher/zipegg

Implementing SPARK-878 for PySpark: adding zip and egg files to context ...