Another pretty major update!

• All assets have been updated to follow a coherent color palette which, along with a bit of 2.5D flair on obstacles, results in a much more polished aesthetic overall
• Weapon drops now roll with common, uncommon, or rare quality, including randomized modifiers
• The inventory has been cleaned up to fix a mouse-hover bug and allow dragging items
• A lot of refactoring to change the way bullets are handled, allowing them to be modified by weapon affixes like pierce or ricochet
• Some basic lighting has been added to the map as a test

Adding modular ship components as random drops that change the look of your ship is still high on the to-do list, and now building an actual level (instead of the wave-based survival) is as well.