Low hanging fruits

There were some suggestions in the jam comments that were pretty easy to do and make for relatively big improvements, so, here they are.

• added arrow/WASD camera controls
• prevent kobolds from memorising currently held flags
• make kobolds forget a flag after its picked up
• slightly increase flag regrab/delete range
• added missing credits
• added a weapon -> gold shop
• more visible cliffs
• animated bunny warrens to make them easier to spot