stoch_simul ignores list of variables for irfs

[albop]

For the example1.mod example, change the list of variables to print for instance with stoch_simul(order=1) y c k;. The irfs still contain exactly the same variables in the same orders.

For a bigger model, independently of the stoch_simul command, I found that it prints the first 8 variables in declaration order and ignores the next one.

[MichelJuillard]

Thanks @albop. Variables' selection isn´t implemented yet. I leave the issue open as a reminder to implement it.