Dock bar spacing inconsistent with automatically adjusted dock icon sizes

Currently, when the dock bar runs out of space for available windows, the automatic resizing does not take into consideration the pixel-based drawing, resulting in occasional inconsistent spacing between icons. 

This is NON-TRIVIAL to fix and needs to be done in a way that minimizes overhead in `ObjDockIcon_SetPosition` and/or the package function that assigns positions and widths.