Fix bug in Bayesian estimation where the filter_step_ahead command produced no output

- Improves documentation of resulting matrices
- Adds unit test for filter_step_ahead option
Added the possibilty to set the initial condition of the (stochastic) extended path simulations with the histval block.
Do not replicate fsdat_simul.m (use the one in tests/fs2000 folder).
Added mod files (and associated steadystate files) for k_filter_ahead in the testsuite.
Various minor fixes to the ref. manual
Release notes for 4.4.0 release
Fix MATLAB version number
adding 3rd order derivatives to Static Model for evaluation of Ramsey
policy computed at order = 2
osr: added optimal value of parameters to oo_.osr.optim_params; moved
osr_example to ./tests/optimal_policy
ms-sbvar: corrected bug in initialization/computation of final subperiod
ms-sbvar: corrected bug in initialization/computation of final
subperiod
Add missing antislashes
Document oo_.osr.optim_params
fix permissions
reporting: for windows filenames escape underscore
reporting: fix figure inclusion for windows
reporting: fix typo
ms-sbvar: corrected bug with final_subperiod default value and
clarified in the manual.
ramsey_policy: correcting the computation of the value of the
objective function; adding details about the period objective function
in the manual.
Adding correction of evaluation of planner objective to NEWS file
(cherry picked from commit 886e78a1ee076cca0a33bf767c763dcb54217a6b)