Updated slicing

Been a while since I worked on this project, but I am back into it with a few updates.

• The slicing system for complex objects (currently just the shelves) has been updated to hopefully avoid issues where pieces are slices off but don't properly detach from the rest of the object
• Sword movement is smoother
• Controls have been tweaked:
  • Right click enters sword mode as before
  • Left click locks on to objects (no more blocking, I'm thinking of removing that in favor of a parry mechanic)
  • Press "0" to reset the level