v0.51 build 4 (Unstable / Testing)

Another build for testing out new features for v0.51 - including:

• The Auto-Crafter bot (and some new fixes for it so that it can collect seeds from Greenhouses).
• Ability to queue up crafting items even when your inventory is full.
• Drop items by dragging them up off the inventory bar.
• Vehicle trailer physics improvements.
• New tooltip for explaining how to recharge and repair vehicles.
• Fixing bugs with items that aren't supposed to stack when crafted (oxygen tanks).
• Trying out a different .jar app wrapper for making native executables.