In process of making better module.
Added SOU.
Finished SL.
Not need T in solver.
Restructure to use classes.
Forgot ref rho.
Forgot to give dt.
Forgot to fetch all class vars.
Forgot rho in arg last in start function.
Fixed correct calling of super.
Calling with combine will give list of methods and lines in start method.
Combine works correctly. TODO get rid of code in start method.