Previous: GeneralProjection extends Projection
The message which a source entity sends to a dest entity
it wants to connect to. By default it contains the source entity
ID and port no, as well as the DestMethod.
ConnectionRequest( EntityID srce, PortID srcPort, DestMethod dm)
Derived connection requests can include extra information
which the destination entity might need to consider, e.g.
the source entity's position, or axon shape.