CAN I USE? - http://caniuse.com/contentsecuritypolicy
referer: https://www.requestpolicy.com/ crp
http://www.html5rocks.com/en/tutorials/security/content-security-policy/
https://status.modern.ie/contentsecuritypolicy
https://www.chromestatus.com/features/5205088045891584
https://docs.webplatform.org/wiki/tutorials/content-security-policy