Importantly avoid color copies for rendering Draw calls in GUIRenderer::UpdateDrawCallCache, CButton::Draw, CChart::DrawAxes, CDropDown::Draw, COList::DrawList, refs #1984, rP1518, rP22637, rP22638.
Also avoid color copies during XML loading in CGUI::Xeromyces_ReadImage, CGUI::Xeromyces_ReadEffects, COList::HandleAdditionalChildren.
Add CGUI::HasPreDefinedColor and mark m_PreDefinedColors, CGUI::GetPreDefinedColor, IGUIButtonBehavior::ChooseColor() as const for consistency with the other "databases", refs rP22637.
Mark CGUIColor as NONCOPYABLE to add compiler errors if there is an unexplicit copy, refs rP22637.
Explicit and ugly copy in CGUI::Xeromyces_ReadColor and CGUIColor::ParseString until refactoring can remove these.
Deregister copying <CGUIColor>GetSetting functions, refs rP1518.
Uses the const ref GetSetting from rP22693.