#38 Improved Layer Handling

[GMFTatsujin]

Add to the interface a list of elements that exist the
label. The listed elements could be ordered within the
list, which would then be reflected in the order by
which the elements would be rendered. This would be a
profound improvement over the current bubble-sorting
method of having to judiciously pick which elements go
all the way to the front or all the way to the back.
The list would also allow for selecting an element
without having to pixel-hunt it if it lived on a
crowded label.