Perf test script
Adds a python script that we can use to run perf tests.
It currently runs icgrep, wc, and csv2json. By default it will run each 10 times and output cycle count results from each run as well as an average across all runs.
It expects to be supplied with a data directory that contains three data files. This directory is supplied in the perftest.zip file in this MR. It's kinda big, but I figured this would be the best place to put it.