added show card functionality to the cards_controller....links to cards on the show user page now work correctly.
Merge branch 'master' of github.com:pschwyter/mtg_json_api

merging card show page updates with master
fixed mana image bug....was throwing an error for cards where mana_cost = nil (lands)
Merge branch 'master' of github.com:pschwyter/mtg_json_api

merging with master....fixed mana image bug...was not displaying 'manaless' cards