[DynareDev] Change in deterministic shocks

Hi,

Since commit 82b311569, temporary deterministic shocks are now initialized differently. Their value is now set in make_ex_.m, while previously their value was directly set into oo_.exo_simul by the preprocessor.

Also, make_ex_.m now unconditionally recreates oo_.exo_simul. Previously it was only recreating it if the variable was nonexistent.

This change should fix various ugly problems and bugs that we had with temporary shocks.

Please however check that it does not break anything. In particular, the change potentially affects all routines which call make_ex_.m; this includes deterministic forecast and extended path.