More levels, more entities, more scores

In this most recent release, Revision 267... I'm not sure who is going to read this, so I'll just go by this quickly.

• Implemented Tubokun, Burokun, and Rokkun. 
  • They work, err... roughly. Polish comes later!
• Added save data.
  • The best score for each level is saved.
  • The save data format may change in the future, and as such is not too-too reliable currently.
  • You can easily reset the save data in the World Map

• Added more levels from the original game.
  • It's not a complete list, but it's interesting to see them working just fine.