Small improvements to correlate executable
Small improvements to correlate executable

* Make correlate handle input files more reliably

  I'm not sure it works for the previous use cases. I'm not worried as I
  believe correlate is just a debug tool left over from Kyle.

* Improve correlate disparity writing abilities

fengzhyuan/visionworkbench,fengzhyuan/visionworkbench,AveRapina/visionworkbench,AveRapina/visionworkbench,AveRapina/visionworkbench,fengzhyuan/visionworkbench,AveRapina/visionworkbench,fengzhyuan/visionworkbench,AveRapina/visionworkbench,DougFirErickson/visionworkbench,DougFirErickson/visionworkbench,fengzhyuan/visionworkbench,DougFirErickson/visionworkbench,fengzhyuan/visionworkbench,DougFirErickson/visionworkbench,AveRapina/visionworkbench,fengzhyuan/visionworkbench,DougFirErickson/visionworkbench,DougFirErickson/visionworkbench