Procedural Control Surface width affects center of lift

[geralddarden]

When changing the width and length of the control surfaces the center of lift is changed asymmetrically.

[geralddarden]

The issue does not seem to occur if using the default width (0.240).

[SIGUSR2]

To be more specific the inbalance occurs only when width@root != width@tip and seems proportional to the both this difference and the length of the control surface.