More Prominent 'Is Liftable' checkbox

Steps to recreate:

1. Quest->Graphics->Combos
2. Click 'Edit' in the Select Combo window
3. Click 'Lifting' tab
4. In the middle frame, observe the 'Is Liftable' checkbox

It doesn't make much sense to change the rest of the data on this tab if a combo isn't liftable, so we could move that checkbox up to the space immediately below the tabs but still above the three frames where it is more prominent and have all the other controls on that tab become disabled if it isn't checked.

This checkbox is created by ComboEditorDialog::view() in comboeditor.cpp

The "Override Selector" checkbox in the Subscreen Settings window is like this.