Add a buffer for proper work with Primitive node.

Primitive node is strictly depends on output type, so I can't to use its output for any other node. There should be a buffer node, where you can select type from a huge list of primitives and then connect primitive to it, or additional outputs for Primitive that will help to process values.

Why is it important? For example, we have a nodeslike Random Number Generator (seed) from primitives, but there is no way to redirect such values elsewhere. What if I just want to save previous random number (actually, a number from current generation)? Extra value output + primitive buffer can help me a lot.

**(Next comes more complicated, but universal concept)**
A one buffer node with possibilities of creation custom inputs and outputs will replace a lot of useless specialized custom nodes. There just should be a dictionary of primitives, where developers will add new primitive types. Every node without internal value processing can be replaced by just one node, so it will be a really useful thing. Also there can be some sort of selectable type of output (if there exists implementation of converting certain input to certain output).