Add 0.01% pixel diff to find last frames (#774)
Add 0.01% pixel diff to find last frames (#774)

We have had a problem picking up too small changes that makes us
use wrong last visual change, see:

https://phabricator.wikimedia.org/T215160
tobli/browsertime,sitespeedio/browsertime,sitespeedio/browsertime,sitespeedio/browsertime,sitespeedio/browsertime