UI Drag/Drop and click to move all working now. Can also buy units by dragging them from the shop instead of clicking

Many updates. UI functionality is pretty close to the main game now.

• Adjusted UI components to fit better
• Drag and drop champions work
• Click to select and drop unit works (can't sell units except using E for now)
• Can drag to buy champions from shop now
• A bunch of under-the-hood bugs fixed