Implementing SPARK-878 for PySpark: adding zip and egg files to context and passing it down to workers which add these to their sys.path
Bug fix for display of shuffle read/write metrics.

This fixes an error where empty cells are missing if a given task
has no shuffle read/write.
Capturing GC detials in TaskMetrics
Correct sorting order for stages
Correcting terminology in RDD page
Small style clean-up
Style cleanup based on Matei feedback
A few small scheduler / job description changes.

1. Renamed SparkContext.addLocalProperty to setLocalProperty. And allow this function to unset a property.

2. Renamed SparkContext.setDescription to setCurrentJobDescription.

3. Throw an exception if the fair scheduler allocation file is invalid.
Renamed setCurrentJobDescription to setJobDescription.
Various UI improvements.
More minor UI changes including code review feedback.
Merge branch 'master' of github.com:AndreSchumacher/spark
adding accidentally deleted hash