TFC : Carry on Storage

• Added weight values to the Knapsack and Backpack
• The Knapsack and Backpack are now able to be placed on tool racks
• Changed the GUI for The Knapsack and the Backpack

The First release of the mod adding:

• Leather sack and Leather strip, Crafted by knapping leather
• Knapsack, crafted with two string and a sack
• Backpack, crafted with two sacks, 4 leather strips, 1 wool cloth and 2 string