Change to use Yarn appropriate directories rather then /tmp or the user specified spark.local.dir
Throw exception if the yarn local dirs isn't set
Update docs and remove old reference to --user option
Allow for Executors to have different directories then the Spark Master for Yarn
Updated based on review comments.
Change Executor to only look at the env variable SPARK_YARN_MODE
Merge pull request #865 from tgravescs/fixtmpdir

Spark on Yarn should use yarn approved directories for spark.local.dir and tmp
Hot fix for command runner
Make local variable public
Adding extra args
Merge pull request #873 from pwendell/master

Hot fix for command runner
Merge pull request #871 from pwendell/expose-local

Expose `isLocal` in SparkContext.
Fix removed block zero size log reporting
Merge pull request #874 from jerryshao/fix-report-bug

Fix removed block zero size log reporting