Inventory and game save

Added a couple things since last time:

• Ship panel where you can manage inventory
• Transfer items from town marketplace to ship inventory
• Transfer items from anywhere to a gun slot to equip a gun
• Transfer items from a gun slot to somewhere else to unequip a gun
• Saving progress locally to continue on

Noticed a couple bugs:

• The Kill Counter somehow doesn't update anymore
• Sometimes a random text field just has a single digit in it, that increments each time (???)