Add simpler color selector

[sebinside]

Add an optional even simpler hue-based color selector, i.e., something like ten base colors to choose from.

[thowi-com]

You could additional add an option for entering a color code (i.e. HEX) after clicking on a cogwheel or a pen. Reason: If I'm using an previously generated icon already and I want to generate a new icon with exactly the same color like the old one, I could pick the color from my old icon and paste it into your tool for the new one.