added basic card draw replacement,

auto=replacedraw choice damage:2

auto=replacedraw choice draw:2 noreplace

notice noreplace exempts the draw from sending a draw event. draw events and drawn events are seperate events.

added dredge and it's rules.

[card]
name=Dakmor Salvage
auto=tap
auto={t}:add{b}
dredge=dredge(2)
text=Dakmor Salvage enters the battlefield tapped. -- {T}: Add {B} to your mana pool. -- Dredge 2 (If you would draw a card, instead you may put exactly two cards from the top of your library into your graveyard. If you do, return this card from your graveyard to your hand. Otherwise, draw a card.)
type=Land
[/card]

projects/mtg/src/AIPlayerBaka.cpp

@@ -602,7 +602,7 @@ int OrderedAIAction::getEfficiency()
     if (!efficiency && may)
     {
         AIPlayer * chk = (AIPlayer*)p;
-        if(may->ability->getActionTc() && chk->chooseTarget(may->ability->getActionTc(),NULL,NULL,true))
+        if(may->ability && may->ability->getActionTc() && chk->chooseTarget(may->ability->getActionTc(),NULL,NULL,true))
         efficiency = 50 + (owner->getRandomGenerator()->random() % 50);
     }
     if (p->game->hand->nb_cards == 0)