Better Hints, Encouragement, Mathematical Symbols

I added a few more cool features.  

The hints are better now.  They are colored based on origin arrow, not destination, which is a better choice.  Also, when you touch a bubble and it outlines in white, its arrows also outline.

The game saves a partial history of games that have failed to crack the latest high score.  It encourages you if you are doing better than recent games, even if you haven't been able to get a new high score.  

Finally, the game is a bit more friendly to beginners.  As one bubble approaches another, the mathematical symbol of what operation will be performed fades in.   Many beginners have a hard time getting the hang of the order of combining bubbles, whether addition or division (or subtraction) is about to be performed.  This will eliminate that guesswork.  It's pretty unobtrusive, so I don't think it will both advanced players.  I may try out different rules about how the symbols fade in.  For now, it's just based on distance.

Enjoy!

P. S.  Sorry to Mac users.  That version isn't updated yet.  It will be another two weeks before I get to that.  All the other versions are updated, though!