Major update

This is a major update that puts the game into final form.  

The biggest update is that scoring is now a bit more forgiving, and more clearly explained in the directions and as you play the game.  Originally, you needed to maintain a streak of solving puzzles without using undo to build up score quickly.  If you so much as used one undo, you would have to start over at gaining only 1 point per puzzle solves.  

Not, anymore.  Solving without using undo (or any other aids) is still the only way to build up the bonus that gets applied at the end of the round, but using Undo only stops the bonus from increasing, it doesn't decrease it.  

Hints are now a lot more informative.  A hint will tell you how many moves out of how many possible of each type (addition, division, subtraction) that lead to a solution.  This can be pretty informative, although it still doesn't explicitly tell you what you can do to move forward.  A hint decreases the bonus by 1 point each time it is used, irrespective of whether the hint required the puzzle to be stepped back or not.  However, you still get at least 1 point for solving the puzzle, even if you use a bunch of hints.  

Using Give Up is the only aid that clears the bonus to zero.  You get a chance to solve the puzzle after seeing a mathematical solution.  If you succeed, you don't score or lose any points.  The only time you lose points is by moving on after seeing a solution, where you lose just 1 point.  

Overall, I think this new gameplay helps to make the aids more usable.  There is less stress to have to always solve the puzzle perfectly,  

I added a tutorial mode (with 4 bubbles) that you must pass before the level select screen is unlocked.  I have determined that puzzles with 5 bubbles are too complex for absolute beginners, but solving a series of 4 bubbles puzzles teaches the major patterns that will be important in the higher levels.  

Finally, I added that the time trial has a separate unlock system than the normal games.   When the Level Select screen is first unlocked, both Level 5 normal and Level 5 time trial are available.  Unlocking the next level only unlocks normal mode for it.  To unlock time trial, you need to reach 20 points in the previous level's time trial.  That may seem like a really tough achievement for beginners, but it should keep more advanced players busy for longer.  

Thanks for playing.  Please download the new version !

Be zen!

P.S.  The Linux version still only works for the latest builds of Linux.  I'm working to fix this issue.