Note that with 0.8.7, it is possible to color a column based on the difference between two dates. Assume your column is called #mydate. The following advanced coloring rule will return the color red if #mydate is within 5 days of today.
Code:
program:
t=days_between(field('#mydate'), today());
test(t, cmp(t, 5, 'red', '', ''), '')
Go to preferences/look and feel/coloring to create the advanced coloring rule.