Improving #107 based on Jussi's comments. Removing un_commodity from input...

Improving #107 based on Jussi's comments. Removing un_commodity from input files - the set is formed based on commodity set as well as p_gnu (it has to have capacity, unit_size or conversionCoefficient). Also, removed automatic calculation of p_uStartupFuel -> it needs to be in sheet p_uStartupFuel even if there is only 1 startup fuel (use fixedFuelFraction = 1)!

inc/1e_inputs.gms

@@ -30,7 +30,6 @@ $ifthen exist '%input_dir%/inputData.gdx'
     $$loaddc unit_fail
     $$loaddc commodity
     $$loaddc unitUnitEffLevel
-    $$loaddc un_commodity
     $$loaddc effLevelGroupUnit
     $$loaddc group
     $$loaddc p_gn
@@ -158,6 +157,7 @@ unit_minload(unit)${    p_unit(unit, 'op00') > 0 // If the first defined operati
 // Units with flows/commodities
 unit_flow(unit)${ sum(flow, flowUnit(flow, unit)) }
     = yes;
+un_commodity(unit, commodity)$sum(grid, gnu(grid, commodity, unit)) = yes;
 unit_commodity(unit)${ sum(node, un_commodity(unit, node)) }
     = yes;
 
@@ -266,15 +266,6 @@ p_unitEmissionCost(unit, node, emission)${nu(node, unit) and p_nEmission(node, e
           )
 ;
 
-// If the start-up fuel fraction is not defined, it equals 1
-p_uStartupfuel(unit, commodity, 'fixedFuelFraction')${ ( p_unit(unit, 'startFuelConsHot')
-                                                         or p_unit(unit, 'startFuelConsWarm')
-                                                         or p_unit(unit, 'startFuelConsCold')
-                                                       )
-                                                       and un_commodity(unit, commodity)
-                                                       and not p_uStartupfuel(unit, commodity, 'fixedFuelFraction')
-                                                     }
-    = 1;
 
 * =============================================================================
 * --- Determine Commodity Price Representation -------------------------------------