* 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.
d9efb408e5