Change options_.lik_init to default value if the fixed point of the Riccati equation cannot be found.

Documents the feature introduced in commit fa9f6ac9. Added more information about option lik_init=3.

Added option lik_init=4. Initialization of the Kalman filter/smoother with the fixed point of the Riccati equation.

  + the number of static, lag, lead and both variables,
  + the lead_lag_incidence matrix for variables related to previous blocks
  + the index of reordered policy rule
for each block during the preprocessing step
- correct a bug in the comment related to first order derivatives in _dynamic.m file for a block decomposed model without bytcode
- avoid simplification of the Jacobian matrix (setting to zero all elements below the cutoff) for  estimated or stochastically simulated models: the cutoff option is set to 0.

- The block-decomposed models can now be estimated