pm3.m: If no TeX names are provided, default to variable names provided

Old default assumes that only moments for endogenous variables considered. This leads to wrong results if e.g. shocks are considered.

(cherry picked from commit 49abff9e4d1ee451d927d78387aebb43726eb613)
Fix selected_variables_only option with classical forecasts

dyn_forecast requires that the smoother has been run on all endogenous variables, leading to crashes. Now, if this option is encountered with classical forecasts, it is overridden. Also documents this in the manual.

(cherry picked from commit 68b27252d7c0a98f7ea8ef731463496f14c6daa2)
Fix computation of SmoothedMeasurementErrors in Bayesian smoother

(cherry picked from commit 45ef721d03bc75a6dbf109afd060363f1e26eae8)