Fix behavior of smoother2histval

The
smoother
will only store theM_.orig_endo_nbr
variables for Bayesian estimation. So callingsmoother2histval
will "forget" about the auxiliary variables we introduce. Thus, by convention they will be initialized at their steady state  which differs from the description in the manual that itwill use these values to construct initial conditions (as if they had been manually entered through histval).
In case of
histval
, the nonmentioned variables would be set to 0.In contrast, for ML it will work.

@MichelJuillard In b70d99d1 the code was refactored. But the treatment of lags seems inconsistent. Initialization assumes one lag via
M_.endo_histval = repmat(oo_.steady_state, 1, M_.maximum_lag);
but later we have
k = M_.orig_maximum_endo_lag  M_.maximum_endo_lag + 1: M_.orig_maximum_lag; v = s((periodM_.orig_maximum_endo_lag+1):period);% + steady_state(j); M_.endo_histval(j, :) = v(k);
which relies on
orig_maximum_endo_lag
and may have more than one lag. Using grep, it seems most other files expectM_.endo_histval
to be a vector not a matrix. 
Depending on whether output is to a file or
M_.endo_histval
, nonrequested variables will be set to 0 or the steady state. We must be consistent.