* Due to a request, added an option to configure the key used for
  diving.

* crash: doAllTests failed in volee with mats agains ivan

* if computer wins ball with a passingShot close to the net, he
  believes he has won by taking the net!

* AI: have computerSkill alter the random error, not the distance from
  the line. That should be fixed.

* AI: split computer tactics into stayBack, attack when opponent tired,
  attack as soon as possible?

* ivan interlocutory shot is too short and diag? 

* ai: learning. The computer should notice you tend to take the net
  after service, and open for topspin.

* sprint sounds looping

* on slow PCs, the impact is not on the racket. this is because
  updateAnim never skips frames

* redraw stretchForward frames

* make the length of frame in walk anim depend on run speed

* computer does not sprint to reach dropshots

* computer never makes mistakes

* computer ignores pc_tendsToAnticipateGroundShots

* when taking the net, pete arrives and then gets back. It is like the
  timer were reset to 0


* in calculating distance, the AI does not take dropshots into account


* add mac, boris (like pete, but more spin) and andre (like ivan, but
  anticipating)

* crashes if I do volee with spin = 0.0, and if service has 0.0 spin

* rip graphics: ivan: forehand and backhand at 20.06. forehand:22.13
  Arovescio:26.19 perfect Brovescio:30.0 perfect, Brovescio 43.57
  perfect, Adritto:36.30 , Adrittov:45.31 , Bsmash:46.50 --- riprendi a 0.50

  mac:Aforehand 22.31,  Arovesciov 22.34 Bdritto:40.50   Arovesciov:43.25 perfetta


* parabola opacity should also depend on running speed.

* interpolate frames

