Semagrams <> AlgebraicDynamics

Summary: Allow users to build compositions of dynamical systems (both the diagram of systems and the elementary models) in Semagrams.

To design the diagram of systems, the user would draw boxes and wires between the boxes. Ports would be inferred from wires or added by the user. Designing the diagram of systems could also be hierarchical. So I can click on a box to draw a semagram inside of it and then zoom out. In the zoomed out version I can either hide the internal semagrams or expose them.

To design the elementary models, the user would do one of three things
- Click on a box and be prompted to fill in the necessary information (e.g. number of states, dynamics, readout or port map)
- Click on a box and choose from a list of available models (these could defined by the user ahead of time or imported from some library of models developed by experts).
- Define an elementary model and a box of the right sort will appear

Once all of the boxes have been filled you should be able to click a button that runs the system with some chosen parameters and initial conditions.