Implemented varying difficulty based on score
Implemented varying difficulty based on score

Time does not scale yet.

There are currently 5 levels:
Lv1 - 2 terms + -
Lv2 - 2 terms + - x /
Lv3 - 2-3 terms + -
Lv4 - 2-3 terms + - x /
Lv5 - 3 terms + - x /

If you're interested in the code, major changes are in the:
- Difficulty variables
- NEW updateDifficulty()
- generateNextQuestion()

You might want to read the last commit too, to understand the new set
system used.

Neil0/numrush,Neil0/numrush