A fix related to issue #112: changed omCosts from p_unit to p_gnu and renamed to vomCosts. It is possible to give vomCosts also to input units, but in that case the user should select the sign carefully. The objective function includes a term:
+ sum(gnuft(grid, node, unit, f, t), + v_gen(grid, node, unit, s, f, t) * p_gnu(grid, node, unit, 'vomCosts'))
which means that positive vomCosts result in decreasing objective function value when multiplied with negative v_gen. Positive vomCosts could be interpreted as an increase in consumer's utility. In this way, this fix may also be able to implement feature #76.