Use generic URIs

Summary:
/diffusion/X/history/?copies=0 is same as /diffusion/X/history/
/countdown/1/?chrome=1 is same as /countdown/1/

Test Plan:
Visit /diffusion/X/history/, click on Show/Hide Copies/Branches twice.
Visit /countdown/1/, click on Disable/Enable Chrome twice.

Reviewers: epriestley, tuomaspelkonen

Reviewed By: epriestley

CC: aran

Differential Revision: https://secure.phabricator.com/D1424