In the rare combination of k_order_solver, pruning, and order=1 the steady state was not subtracted from the starting values when doing simulations

Currently, all stochastic solvers put the error code to info(1) and use
print_info to output the error. The only exception was k_order_pert,
which immediately created an error. Thus, the use of k_order_pert did
not allow for continuing after encountering errors, because only
print_info obeys the noprint-option. Replacing mexErrCheck by setting
info should deliver the correct behavior.

This reverts commit 2815d5fb.

For parallel computations, the relative path is necessary.

-) estimation options for data set must be given also when ppost=1 (fix in testsuite);

Previously, the strings were concatenated, rendering calls to strmatch
wrong. Changed to cell arrays on which strmatch operates.

Proper use of dataset_ structure and remove the dangerous dat_fil_ utility;
Added r2 in output.

Increased linewidth and changed color to differentiate from background
grid.

Closes #329

option

If the mode_file option was used, xparam1 was reloaded from the
mode-file after the initial checks, sometimes leading to very cryptic
errors. Now the initial checks already load the correct parameter
vector.

Also make the plots obey the nodisplay option

If info(2) is really empty. it cannot be accessed by isempty.