Ref. #1680: perfect foresight

See merge request Dynare/dynare!1833

Ref. #1680

Ref. #1680 : 2nd-order welfare

See merge request Dynare/dynare!1828

The “io” package is a dependency, hence must be explicitly installed first.

[skip ci]

Ref. !1831

Ref. !1830

Ref. !1829

See !1827

[skip CI]

fixed names of files, removing spaces and dots
use writetable with mac OS

condition computation of posterior statistics also to (options_.load_mh_file && ~options_.load_results_after_load_mh) and apply it to all cases

autocov is initialized NaN with the original order and then only loop up to updted order compatible with sample size.

adjusted message in case of diffuse filter, where cointegration is most of the time the reason for such a warning

Ref. preprocessor#63

Under Octave, the +ols folder conflicts with the builtin ols() function.