1.3 GW - Updated game version

- Video background in main menu
Single game:
- From 34 to 19 enemies + optimisation
- Texts changes

1.2 GW - Updated game version :

- Changed background and animated main menu
Single game:
- demarcated rock (collisions fixed)
- added a new cloud system in the sky
- changed interfaces and info texts
- added music
- made numbers over enemies
- T-rex is seen at the beginning of the mission
Multiplayer:
- demarcated rock (collisions fixed)
- added a new cloud system in the sky
- Simplified leveling by experience
- changed the path of the t-rex