[css3-values] feedback

Please consider adding an abs() operator for calc().

This simple operator would enable mathematical workarounds for the lack of
max() and min(), which I understand was apparently eliminated from the spec
due to complexities in performing the comparisons.

An abs() function would make it possible to calculate either max() or min()
using simple functions:

max(x, y) = (x + y) / 2 + abs(x - y) / 2
min(x, y) = ((x + y) - abs(x - y)) / 2


Thanks for your time.