plot.lm: "Cook's distance" label can overplot point labels

Dear John and Brian,

My point about colour-blindness was partly tongue-in-cheek, but I think that
it's a bad choice to have the second and third colours in the default
palette as red and green.

Looking at the standard palette with dichromat::dichromat() it seems that it depends on which flavour of red-green anomaly you have. For deuteranopia the red and green are quite close. For protanopia they are pretty distinct and the confusion is between colours 3 and 7 (yellow vs green) and between 4 and 6 (blue and magenta).

I agree that the standard palette isn't ideal, though.

      -thomas

Thomas Lumley			Assoc. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle