Blender Git Loki

Node select: refactor, fix some inconsistent behaviors in socket selection.

Refactor a bit node selection code, mostly in the socket selection in
one place 'extend' logic usage was inverted, deselection of other
sockets/nodes was not working properly.

Also now make node active when selecting a socket, this makes more sense
and makes the NODE_OT_link_viewer macro much more useful (this is the
only user of the 'socket select' feature currently, afaics).