Additions

• Added granite top/side CTM detail
• Added normal/spec maps for smooth stones building components
• Added diorite top/side CTM detail
• Added string item model
• Added snow ball item mode

Tweaks/Fixes

• Refactored overlays for new granite/diorite CTMs
• Remade granite overlay
• Remade diorite overlay
• Tweaked wall/stair/slab UVs for diorite/granite/andesite
• Updated stone item texture
• Fixed incorrect cullfacing on stone stairs