Remove references to removed variable sets

CastorModel/main.m

@@ -35,10 +35,6 @@ mutable_variable_names = ["r_w", "L_ex", "L_ey", "L_df", "sigma", "phi_x", "phi_
 % castor_variable_set: Selects a set of parameters for the castor wheel such as wheel radius and mass etc.
 %   'rand':     Random parameters within somewhat reasonable bounds
 %   'sym':      Symbolic, will break matlabFunction generation in other functions
-%   1-4:        Obsolete
-%   5:          Reality-based guess for feasible parameters with large sigma
-%   6:          Same as 5 but for a regular upright castor wheel    
-%   7:          Same as 5 but for a regular upright castor wheel with nonzero L_ey
 %   12:         Used for MSc thesis
 %   13:         Treadmill experiment castor wheel  
 castor_variable_set = 13;