plot.sh: plotting histograms by the result of interbench

Dependency:
 - gawk (awk is not supported)
 - gnuplot
 - bash

Usage:
plot.sh [options] files

options:
	-o: output png file name, default: "output.png"
	-c: which column to plot, default: "latency"; candidate: "max_latency" "desired_cpu" "deadlines_met"
	-m: which simulated scene to plot, default: "Audio"; candidate:"Video" "X"

"files" could be a list of files of interbench output, which will be plotted as clusters.

Note: Each file should contain only one test result.

Author: Brills Peng (brillsp@gmail.com)
