Set up player inventory

[jakeHaasBlog]

• [x] Player inventory can hold up to six creatures
• [x] Player can change the order of creatures from the player inventory
• [x] Inventory shows images of each creature and their stats
• [x] Player is able to choose which creature is equipped
• [x] Shows equipped creature's battle actions
• [x] Can remove creatures from inventory

[jakeHaasBlog]

Not pretty, but everything is functional. May add a confirmation button for removing creatures from inventory