fix for cumulative upcost, extra cost were not being multiplied

[card]
name=Phyrexian Soulgorger
auto=cumulativeupcost[{S(creature|myBattlefield)}] sacrifice
text=Cumulative upkeep - Sacrifice a creature. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
mana={3}
type=Snow Artifact Creature
subtype=Construct
power=8
toughness=8
[/card]
was only charging you 1 sacrifice per upkeep.

added thisTargetComparison, this(cantargetcard(targetchooser))...its a thisdescriptor that compares if the card can be targeted by a target chooser...

projects/mtg/include/ManaCost.h

@@ -77,6 +77,7 @@ public:
     // Extra Costs (sacrifice,counters...)
     //
     int addExtraCost(ExtraCost * _cost);
+    int addExtraCosts(ExtraCosts *_cost);
     int setExtraCostsAction(MTGAbility * action, MTGCardInstance * card);
     int isExtraPaymentSet();
     int canPayExtra();