#308 Dark mode vs light mode

[corelanc0d3r]

Hi, after changing the GUI to dark mode, it doesn't seem to reset back to light mode when I deselect "dark mode".
Also, in dark mode, the board coordinates are displayed in black, which makes it difficult to read.

[Jens Nissen]

You need to restart ChessX after mode changes.
Option to change coordinate colors in 1.5.9