Removed some extraneous cards from table

Changed card graphics to match final Kickstarter printing

- Fixed issue with thumbnail image

- changed the game thumbnail to the card back image

-Updated 360 background. Taken by one of the developers in the great saltpetre cave!
-Added tablet with URL pointing to http://www.gonecaving.com/documents/gone_caving_rules.pdf so the instructions are right there for you
- added 2 more "Gameplay quick guide cards" for a total of 6