conditional forecasts: allow using vectors in blocks

Closes #1949

(manually cherry picked from commit 74bc73e7)

preprocessor @ 6e981b8a

-Subproject commit a1bfb5483d76715873f0689d9389793a0838a485
+Subproject commit 6e981b8a7f256a40cac45c37a73022ae1d6597d7

tests/conditional_forecasts/1/fs2000_cal.mod

@@ -78,5 +78,22 @@ end;
 
 conditional_forecast(parameter_set=calibration, controlled_varexo=(e_a,e_m));
 
+results_1=struct2array(oo_.conditional_forecast.cond.Mean);
+
 plot_conditional_forecast(periods=10) gy_obs gp_obs;
+xx=[0.01 -0.02 0 0 0];
+conditional_forecast_paths;
+var gy_obs;
+periods  1:5;
+values   (xx);
+var gp_obs;
+periods 1:5;
+values  0.05;
+end;
+
+conditional_forecast(parameter_set=calibration, controlled_varexo=(e_a,e_m));
+results_2=struct2array(oo_.conditional_forecast.cond.Mean);
 
+if max(max(abs(results_1-results_2)))>1e-10
+    error('Interface wrong')
+end