TEZ-1285. Add Utility for Modifying Environment Variables. Contributed
by Jonathan Eagles and Oleg Zhurakousky.
TEZ-696. Remove implicit copying of processor payload to input and output (bikas)
TEZ-1089. Change CompositeDataMovementEvent endIndex to a count of
number of events. Contributed by Chen He.
TEZ-1119. Support display of user payloads in Tez UI. (hitesh)