Style all error messages to be the same, where applicable

This was discovered when I tried to modify Atlassian Renderer to adopt AUI.

At the moment the .error class in master.css is using a pink-ish red colour (#fcc) for error messages.

This needs to be made transparent as it's creating a conflict when trying to use AUI - as can be seen from this screenshot: screenshot.jpg. The Error icon has a darker pink colour as a result.

It's not that easy to change however as there are at least 35 usages of this class (found when searching for class="error" in IDEA). But it's a necessary evil to maintain uniformity across our product.