Colored + readable error messages

Hi! I thought it would be nice to have error messages colored when html_errors is on - fatal errors in red, warnings in blue, notices in green or alike. And since it sometimes happens that error messages are printed on a dark background and are not readable very good, i thought they should be printed on a white background. I wrote a small patch to do this, could you have a look at it and tell me what you think? I attached the cvs diff. Stefan