added countertrack(counterstring) MTGAbility

what this does currently is remove a counter of the type counterstring and when the ability is destroyed it puts the counter back for us.
meant for weapons used as follows.
auto=teach(creature) countertrack(0/0,1,hand)

when the creature is equipped with this weapon it will remove a hand counter from the creature, when you remove the weapon, or the weapon is destroyed or whatever...it will put a hand counter back on the creature.

added dualwielding thisdescriptor...
auto=this(dualwielding) 2/2
auto=this(dualwielding) firststrike

enabled "restriction{" on phasebased triggers @next and @each...

i will work more on countertrack to extend it to domains if it currently isnt possible to use it in this case(haven't tested it on domains)....

projects/mtg/include/ThisDescriptor.h

@@ -133,6 +133,14 @@ class ThisDamaged:public ThisDescriptor{
     ThisDamaged * clone() const;
 };
 
+class ThisDualWield:public ThisDescriptor{
+ public:
+    virtual int match(MTGCardInstance * card);
+
+	ThisDualWield(int dualWield);
+    ThisDualWield * clone() const;
+};
+
 class ThisPower:public ThisDescriptor{
  public:
     virtual int match(MTGCardInstance * card);