* optimized card loading. There was some redundant code that wasn't necessary.

* getCardByName seemed to have a initialization error if you tried to use it before the entire game loaded.  The cache would
throw an exception if you tried to use find and it was empty.  I put a guard around it to avoid this issue.

* refactored Zeth's "toggledifficuly" feature to be stored in meta data.  http://code.google.com/p/wagic/source/detail?r=3106
 -- This is slightly modified as it forces a 1 for 1 swap of cards that are specified.
    from the example given this is how it seemed to be used anyways.
 -- since all the information is stored in the meta data, there's no need to alter the deck's
    definition.

projects/mtg/include/DeckMetaData.h

@@ -24,6 +24,7 @@ private:
     string mAvatarFilename;
     string  mColorIndex;
     
+    map<int,int> mAlternateCardMap;
     // statistical information
     int mGamesPlayed, mVictories, mPercentVictories, mDifficulty;
 
@@ -44,6 +45,7 @@ public:
     string getColorIndex();
     int getAvatarId(int deckId);
     string getStatsSummary();
+    map<int,int>& getAlternateMappings();
 
     int getDeckId();
     int getGamesPlayed();