One of differences in 1.6 compared to its previous releases 1.x, as previously noted, is in order to be compatible with GNOME/GTK 3.8, zonColor 1.6 introduces creation of actual GTK themes for color variant, rather than just make use of GTK-color-scheme feature that has been removed from GNOME/GTK 3.8.
For this release, I included some additions, one of them is new icons. Some people may like flat, square-framed icons, but me, I like icons that looks natural, 3D-shaped, shiny and glossy, and easy to be distinguished. This is a work in progress -- for now, I created icons for some apps, but for future releases I plan to create other icons too. And I also plan to include more than one icon template, so that users can have more choices of icon shape/style in creation of icon theme variant.
