New release

Well, it is again a testing release but it allow us to show the progress of the project.

Visible new since the last release are :
- Plee has a "walking" animation,
- each player can ask the camera to focus him,
- when a player is outside the screen, an arrow display the direction where he is,
- Plee can walk on slopes, and his speed is adjusted according to the strength of the slope (buggy)

We have done a lot of code improvement too and the program is more modular now.