Logo and card back refresh

~ Updated the back of the card, cleaner lines, slightly more modern.
~ Updated game icon/logo
Icon changes

+ added updated mac icon that was missing
~ resized cockatrice.png
Fixed svg for icon

For some reason there was an issue with making the creature image white,
i found a workaround. Icon should now display correctly.
Merge pull request #352 from poixen/image-refresh

Image refresh