Connector

A connector combines several neurons, input neurons, or output neurons, which can be manipulated as one unit. The main purpose of connectors is to quickly connect modules in analogy to physical plugs and sockets. There are two types of connectors: Connectors are created from a group of input neurons or output neurons by the make connector command.
 * Input connectors consisting of input neurons
 * Output connectors consisting of output neurons

Operations on connectors:
 * Move - Move the connector. Connected pipes are pulled along.
 * Rotate - Rotate arround the center of the connector.
 * Delete - Delete the connector and the contained input/output neurons.
 * Disconnect - Transform the connector back to individual neurons of the appropriate type.
 * Plug connector - Combine an input connector and an output connector. The result is a set of independent neurons. This command is the reason why there are connectors in the first place.