[Bf-committers] Change to custom nodes output drawing

[Lukas Tönne]

Custom node output sockets are missing a feature to allow drawing buttons:
http://blender.stackexchange.com/questions/2740/bug-of-the-socket-output-is-not-it

I have a simple patch ready to implement this, but would not sure if this
should go in at BCon3 (considering how touchy API changes are):
http://www.pasteall.org/45431/diff

There are no changes to any existing nodes, but pynodes scripts will need a
small update to draw in the usual way (only display label on outputs), as
shown in the custom_nodes template:

     def draw(self, context, layout, node, text):
-        if self.is_linked:
+        if self.in_out == 'OUT' or self.is_linked:
             layout.label(text)
         else:
             # draw full property buttons here

Would it be ok to add this in trunk at this stage?