Updates the error/notice box with cleaner look, softer colors.
Summary: These colors are more inline with the look and feel and match the table colors.
Test Plan: Used Inspect Element to test each color combination on an error page.
Reviewers: epriestley, btrahan
Reviewed By: epriestley
CC: aran, Korvin
Differential Revision: https://secure.phabricator.com/D4593