[Bf-codereview] Extended UILayout for node drawing (issue 14433064)

[brechtvanlommel at gmail.com]

I did not look into the code, but I have some doubts about this. If we
start customizing these node layouts, it seems to become more difficult
to have different types of node drawing like vertical, or tree style
drawing like in the material editor, or more compact nodes that do not
include so many buttons. Rather than having generic code, all these
variations now have to be taken into account in such draw_buttons
callbacks?

Maybe there's a good use case for this but I don't understand it well,
can you explain why this is needed?

https://codereview.appspot.com/14433064/