New color-picker in trunk

After years of a color-picker that simply cannot pick the colors I
want, I have adapted Pharo's color-picker to be more in the style of
Squeak and integrated it into the trunk.

To use, set "Use the new color-picker" in preferences.

modalColorPickers is ignored for the new color-picker.

It cannot select a color from the world, although this would be a
welcome enhancement.

 - Chris