alg_TWM-PWRFFT wrapper issue for too ideal data

[KaeroDot]

alg_wrapper.m in alg_TWM-PWRFFT got issue that for ideal data (simulated, e.g. during testing), it can happen the S is smaller than P because of the numerical rounding. And if P is greater than S, it will lead to complex Q and this will create error in a later code.
Therefore some comparison with numerical precision is needed.
Could be solved by this code - replacing lines 211-212:
Q = (S^2 - P^2)^0.5sign(Q_bud);
u_Q = ((S^2u_S^2 + P^2*u_P^2)/(S^2 - P^2))^0.5; % ###note: ignoring corelations, may be improved

by code:
SmP = S^2 - P^2;
if abs(SmP) < 2eps
SmP = 0;
end
% If abs(SmP) is greater than 2eps, and is negative, it will lead to
% complex Q and will create error later.
Q = (SmP)^0.5sign(Q_bud);
u_Q = ((S^2u_S^2 + P^2*u_P^2)/(SmP))^0.5; % ###note: ignoring corelations, may be improved