Floor graphics are now drawn one layer at a time, rather than one tile at a time

• Improved lighting
  
• Fixed graphics buffer corruption
  
• Improved shader compatibility
  
• Depth buffers now use rgba8 instead of rgba32f
  
• Tile height, floor and wall are now chosen separately
  
• Explosions only destroy walls with 3 or more damage
  
• Added more walls and floors to the level editor (WIP)
  
• Greatly improved most food items
  
• Added new item - Jam on Toast
  
• Added new item - Spurs
  
• Added new upgrade - Jam Jar
  
• Added new enemy - Raven (WIP)
  
• Added new enemy - Penguin (WIP)