freetype: Update examples to use explicit colors.

R=rsc
CC=golang-dev
http://codereview.appspot.com/1848055

example/raster/main.go

@@ -119,11 +119,11 @@ func showNodes(m *image.RGBA, ns []node) {
 		var c image.Color
 		switch n.degree {
 		case 0:
-			c = image.Aqua
+			c = image.RGBAColor{0, 255, 255, 255}
 		case 1:
-			c = image.Red
+			c = image.RGBAColor{255, 0, 0, 255}
 		case 2:
-			c = image.Red
+			c = image.RGBAColor{255, 0, 0, 255}
 		}
 		if c != nil {
 			m.Set(x, y, c)

example/round/main.go

@@ -72,7 +72,7 @@ func main() {
 			theta := math.Pi * float64(j) / (n - 1)
 			dx := raster.Fix32(r * math.Cos(theta))
 			dy := raster.Fix32(r * math.Sin(theta))
-			m.Set(int((cx+dx)/256), int((cy+dy)/256), image.Yellow)
+			m.Set(int((cx+dx)/256), int((cy+dy)/256), image.RGBAColor{255, 255, 0, 255})
 		}
 	}