From google's documentation:
The analytics.js snippet is part of Universal Analytics, which is currently in public beta. New users should use analytics.js. Existing ga.js users should create a new web property for analytics.js and dual tag their site. It is perfectly safe to include both ga.js and analytics.js snippets on the same page.
However, I can't seem to find a way to set up a filter to exclude my own traffic with a cookie. There is this for ga.js, but as far as I can tell there is no way to set a custom variable with analytics.js, and I get get a custom dimension to work.
Edit: What I've done thus far:
ga('set', 'dimension1', 1);
my websitetraffic is not ignored
Why not just set your own cookie and check against it using the opt out var?
window['ga-disable-UA-XXXX-Y'] = true;