DesignBox

- Marked procedure as overload not virtual - my son was chatting to me, that's my excuse :-D

- SelectionRectPaddingPx: added a way for TDesignBoxBaseItem's to increase/decrease the size of the selection rect

Merge branch 'main' of https://github.com/gmurt/DesignBox into main

- fixed bug in redraw that didn't appear to draw the background color correctly (style set to bsClear not bsSolid)

Merge pull request #1 from gmurt/add-license-1