Creates Executors tab for application with RDD block and memory/disk used, solves SPARK-808
Changed table format for executors
Merge branch 'master' of https://github.com/mesos/spark into ui-808
Fixed memory used/remaining/total bug
Shows number of complete/total/failed tasks (bug: failed tasks assigned to null executor)
Executors UI now calls executor ID from TaskInfo instead of TaskMetrics
Split task columns, memory columns sort by numeric value
Merge pull request #719 from karenfeng/ui-808

Creates Executors tab for Jobs UI