QskMenu needs current and selected states

[uwerat]

In the menu of a combo box we have:

a) the option that corresponds to the value of the combo box b) the option that is related to the navigation by the user ( arrow up/down )

In Qt these are sometimes referred as: "selected", "current".

Displaying the current index is covered by the existing implementation, while the selected index needs to be introduced. We also need 2 states ( Current + Selected ).

Motivation: In the fusion skin the selected index is displayed using "QFont::DemiBold" font weight.