Systray X Margins tuning around the clock

Clock-X-Margins-Tuning.patch aims to increase the margins around the clock a bit to better meet the look of 2k3 and XP.
result: Clock-X-Margins-Tuning.webm

It's not Pixel-Perfect, but the best I could achieve with our existing symmetric margin.
For Pixel-Perfectness we'd need an asymetric margin left and right the clock.

The perfect margin right of the clock would be 5 Pixels, left margin needs to be smaller than that.