#24 Gels and Arrows In Diagrams.

[Robert Luben]

I know this is an odd request considering that only one interface
has this feature (USCL/Gameparlor) at this time.

SCID uses an elegantly simple implementation, here's are some
examples...

[%mark e4 red]

Colors the square e4.

[%arrow b3 f7 red]

Etc

I think this feature would be invaluable for your lecture bot and for
players examining games and for tutoring.

Rob