Large Tent

I've added a larger tent than the one already in the game. There are 3x3 squares of floorspace and it totals 5x5 when set up. 

I've added:
- An iuse function for the large tent
- An iexamine function for the groundsheets of the tent
- Two furniture objects to facilitate the takedown of the tent
- The actual tent in the tools.json file
- The tent into the item group json

The tent has a volume of 40, making it troublesome enough to lug around that it's not a must-have item for the player.