Single Group Input node

For complex node groups, with lots of tweakable parameters, the "Group Input" node will become a mess. Transport these inputs along the tree is one of the main sources of mess in the node editor. The solution for the second problem is, generally, to add several "Group Input" nodes. However, It will be a big ball hard to work.

A much cleaner solution would be to add a "Single Group Input" node, that will output only the value of a single input, chosen from a menu.