Second version uploaded

Uploaded the second version of my checkers.

Added:

* Fluid movement of the stones.

* Stone capture animation.

* Endgame screen.

Plans for the future:

* Fix drag'n'drop (it works better now, but sometimes the movement still doesn't register).

* Fix ugly scaling/aliasing issues.

* Add promotion animation.

* Add captured stones counter (?).

* Add current player indicator.

* Enable undoing moves.

* Add stone setup animation.

* Add AI with difficulty slider.