This ensures that color picks that have multiple issues will
have them all checked at the same time, including ensuring that
the fix for one issue doesn't cause another issue.
Handling of the onError action has been changed from being called
at once to collecting the potential errors in a HashSet to deduplicate
them and then calling onError after a valid color has been found.
(Otherwise you would in the worst case get 256 error messages logged!)
If the picked color and a forbidden color are identical (like
if they both picked the same palette color and in the special case
when a picked color is outside of the allowed range and the method
returns the picked color as the forbidden color),
the vector between them is zero and the maths for adjusting
the color fails by hitting the iteration limit. This changes
the zero vector to the smallest possible vector in order to
avoid the issue.
This can result in some seriously close adjustments in the case of
picking identical palette colors, which might
be undesirable compared to picking a new palette color.
The failsafe in ColorValidator aborts after 255 iterations of
adjusting the color and picks a random color. This message makes it
clearer to the user. Results in two messages being displayed,
first one about adjusting and the about a random color pick.
