chore(performance): check actual accuracy of stimuli presentation

[eladzlot]

from @baranan
These are the links I saved for myself on the matter:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0067769

Black Box Toolkit
http://www.blackboxtoolkit.com/howtobuy.html?tab=1#BBTKv2_pricing

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0085108

[eladzlot]

http://www.sitepoint.com/speed-index-measuring-page-load-time-different-way/
http://www.chromium.org/developers/telemetry

It seems the questions that interest us is the accuracy in which we time stimulus displays