Make selected mode always obvious in screenshot

[gregorulm]

I sometimes take screenshots of my games. However, the G1 modes are ambiguous. Just from looking at a screenshot, it is not possible to determine if a game was played in G1 Master or G1 20g as both frames are grey. I therefore suggest modifying the frame for G1 20G. Gold would be a choice in line with the aesthetics of the game that inspired this mode, which turns the timer golden in 20G, Alternative, a text label could be added. My preference would be to use a unique color for the frame, though.

[FelicityVi]

Thank you for the suggestion. I've added a golden frame for G1 20G to address this (5a3a941).