Better color tools: color editor in the main window.

[TheGoklayeh]

We need to be able to easily edit colors in the main panel. With the different value systems (RGB, HSV/B, HSL). It doen't have to be big nor complex, something like this would be enough:

This would allow to easily modify colors, use them, and add then to the current palette.

[Calinou]

Other useful things:

Please create one issue per feature request after searching for possible duplicates. This makes it easier to check off individual features once they've been implemented.

[TheGoklayeh]

Please create one issue per feature request.

Hi, I'll change that, just wanted to avoid spamming the place.

[OverloadedOrama]

This is implemented in #953.