Nimrina colors updated

I haven't made much progress with Nimrina yet -- I sort of got
sidetracked reorganizing the color chart.

http://www.io.com/~hmiller/png/nimrina-colors.png

Unlike some of the other charts (Tirelat, Lindiga, Minza) I haven't made
any attempt to line up complementary colors opposite each other.
Instead, this chart is based on the idea of a red-green axis and a
yellow-blue axis, with colors spaced as equally as possible around the
circle. So every day I open the color chart and want to move the colors
around again. I tried coming up with some more quantifiable way to pick
these colors, but the results ended up worse. So I finally just decided
to pick a set of colors and call it the "official" Nimrina color set. Of
course, these are just the prototypical colors for each of these color
words; each word represents a range of possible colors.