To do list

[TAJD]

Moving the to-do list from the readme:

1. wrap rig into yacht class, and update measure functions
2. validate on YD-41 (Principle of Yacht Design), and write tests
3. optimize the boat velocity with the 3-DOF equlibrium as constraints (Lagrange multipliers)
4. Add all the windage contributions (mast, crew, rigging, etc.)
5. Optional Delft hydro model
6. Add dagger boards to the possible appendages
7. tidy plotting and results