Added extramempercent option.
Added extramempercent option.

This adds some padding to mapreduce.map.memory.mb.
The problem was the process RSS was crossing the threshold and YARN
was killing the container before ICE had a chance to kick in.

111t8e/h2o-2,vbelakov/h2o,elkingtonmcb/h2o-2,h2oai/h2o,elkingtonmcb/h2o-2,rowhit/h2o-2,100star/h2o,eg-zhang/h2o-2,111t8e/h2o-2,100star/h2o,h2oai/h2o-2,eg-zhang/h2o-2,111t8e/h2o-2,100star/h2o,calvingit21/h2o-2,calvingit21/h2o-2,vbelakov/h2o,h2oai/h2o,100star/h2o,vbelakov/h2o,eg-zhang/h2o-2,rowhit/h2o-2,eg-zhang/h2o-2,h2oai/h2o,100star/h2o,h2oai/h2o,h2oai/h2o,111t8e/h2o-2,111t8e/h2o-2,vbelakov/h2o,elkingtonmcb/h2o-2,h2oai/h2o,eg-zhang/h2o-2,rowhit/h2o-2,vbelakov/h2o,h2oai/h2o-2,eg-zhang/h2o-2,eg-zhang/h2o-2,elkingtonmcb/h2o-2,rowhit/h2o-2,rowhit/h2o-2,111t8e/h2o-2,h2oai/h2o,eg-zhang/h2o-2,h2oai/h2o-2,calvingit21/h2o-2,calvingit21/h2o-2,vbelakov/h2o,elkingtonmcb/h2o-2,h2oai/h2o-2,h2oai/h2o,111t8e/h2o-2,vbelakov/h2o,rowhit/h2o-2,rowhit/h2o-2,h2oai/h2o-2,rowhit/h2o-2,100star/h2o,rowhit/h2o-2,elkingtonmcb/h2o-2,calvingit21/h2o-2,h2oai/h2o-2,vbelakov/h2o,h2oai/h2o,calvingit21/h2o-2,100star/h2o,elkingtonmcb/h2o-2,eg-zhang/h2o-2,calvingit21/h2o-2,elkingtonmcb/h2o-2,h2oai/h2o-2,100star/h2o,rowhit/h2o-2,vbelakov/h2o,h2oai/h2o-2,eg-zhang/h2o-2,calvingit21/h2o-2,h2oai/h2o,h2oai/h2o-2,100star/h2o,elkingtonmcb/h2o-2,111t8e/h2o-2,111t8e/h2o-2,calvingit21/h2o-2,111t8e/h2o-2,h2oai/h2o-2,vbelakov/h2o,elkingtonmcb/h2o-2,calvingit21/h2o-2