More assets and tutorials

I've added numerous tutorials and assets to the growing page of free video game development page. There is still more to be added in the future.

List of the following Ren'py tutorials:

1. Creating an image gallery (beginner)
2. Creating a replay gallery (beginner)
3. Learning image Gallery 2 (beginner)
4. Learning Galleries, image and replay gallery combo (beginner)
5. Learn how to implement Cheats via cheat phrase system (beginner)
6. Learn how to implement Cheats via cheat phrase system part 2 (beginner)
7. Learning Hubs 1 (beginner)
8. Learning Hubs 2
9. Learning Implementing Item Shops 1 (beginner)
10. Learning Implementing Item Shops 2
11. Learning Implementing Item Shops 3
12. Learning Day cycles/phases 1 (beginner)
13. Learning Day cycles/phases 2
14. Learning Music Player 1
15. Learning Music Player 2
16. Learning Preference Options 1
17. Learning Preference Options 2
18. Learning: Simple Game 1
    
    I've included character cards for female characters and some scenes for Chara Studio