srgb - pretty ui!

fixes CNVS-11251

test plan
=========

* general regression test of srgb
* general accessibility test of srgb
* compare prettiness with mockup http://cl.ly/image/40451W2q2E1L/o
* check that errors render correctly

Change-Id: I43c01c08ee591743ef19ed268661841cf54c0e3f
Reviewed-on: https://gerrit.instructure.com/31406
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Simon Williams <simon@instructure.com>
Product-Review: Aaron Cannon <acannon@instructure.com>
QA-Review: Amber Taniuchi <amber@instructure.com>