fill argument for `plot.ped()`

[magnusdv]

This is implemented now, as of 5348064:

library(pedtools)
x = nuclearPed(1)

# Fill colors
plot(x, fill = 2:4)

# Specify individual filling
plot(x, fill = c(`3` = 2))

# Or group-wise
plot(x, fill = list(blue = founders))

# Colored outline and fill
plot(x, fill = 2:4, col = 1:3, lwd = 3)

# Linetype
plot(x, lty = c(`3` = "dashed"), symbolsize = 1.5)

^{Created on 2023-04-19 with reprex v2.0.2}