see MenitItemMorph>>icon, MenitItemMorph>>icon:, MenitItemMorph>>hasIcon and MenitItemMorph>>drawOn:
MenitItemMorph>>minWidth and MenitItemMorph>>minHeight consider the icon (if it's present)
add a set of icons to the world menu.
new Preference's option named menuWithIcons (in menus category)
see class MenuIcons
a set of icons with an appropiate license is needed
the icons get grayScaled when the menu item is filtered
new Preference's option named #menuAppearance3d. this new option uncouple the 3d appareance behaviour from menuColorFromWorld option. now each option handle an aspect
it's possible to have a flat menu with the color from the world, a 3d menu with a color different from the world, etc.
new preference parameter named #menuLineColor.
remove of unsed preferences (#menuLineLowerColor and #menuLineUpperColor)
