minigui: DropdownSelection - set options

[whitebyte]

I couldn't find a way to conveniently set options in one pass. This is what I do now:

auto dropdown = new DropDownSelection();

foreach (el; myOptions) {
    dropdown.addOption(el);
}

It works, but it's kinda clunky. Would be nice to be able to pass the whole options array either to the constructor or to options (currently it's a getter). Or maybe both

[adamdruppe]

i need to do drop down checkboxes too at some point, so maybe i can look at all of it at once since the options may need to change to support that..... well that's probably a different class but ill think about it as i go