Node management internal to Node class

Instead of arranging nodes in an array and saving it in the noe class,
every time we make a node we just map it to itself via it’s hash-based
key. Then we don’t have to do any magic outside at all.
Feedback loop added, output selection deleted

The final result is feed back into the system at this level, so the
final result of building the nodes outputs to the order of the equation
- 1 to be integrated.

Also, output selection is removed as it can more readily be addressed
at a higher level of abstraction considering we might be outputting the
variable representing the order of the equation.
Removed unnecessary output
Readout (output) handled in fanout.

Outputting some order variable is taken care of here. Now we have to
deal with it if it is of order 0 through N-1 in one case and order N
(where the order of the equation is N) in the other (different
topology, latter requires extra fan after the fact).
Added output as a symbol to consider in state

This is needed since we need to deal with items of the form {:type =>
output, :ref => 0} and don’t want to worry about special case troubles.
Generating Wiring Connection objects

This is the final stage before code generation. There are some bugs to
track down and think about, but then we’ll be at the point where we can
output C.