simplified and corrected Imgur ruleset

Hello there. I'm Bryn, an Imgur employee. It came to our attention that there were issues with our ruleset and functionality. Since we now have full HTTPS support on imgure.com and its subdomains, I've simplified the ruleset and made corrections. I've tested this ruleset both stand-alone and with the Imgur Uploader Extension (v1.06 - not developed or owned by us at Imgur). All seems well FWIW.