Scroller nub dragging.
Added min, max and clamped macros.
Draw scroller value.
Added vertical scroller support.
Add virtual destroy method to widgets.
Added list widget. Not interactive yet, just some internal logic and drawing.
Added convenience functions for wz_widget_set_size etc. that take individual args instead of structs.
Clip wzList items rect to widget rect.
Sanity check scroller values.
Added scroller value change callback. Plugged it into list widget, so it can now be scrolled.
Don't need to memcpy to copy structs of the same type.
List widget item hover.