Change default theme with button

[ZePorko]

Add button to change default theme
default.zip>>default2.zip>>default3.zip

No need to save preference theme default.
Game with dedicated theme keep priority.

[camarade35]

Load Default Theme by genre <genre>puzzle</genre> or <genre>fighter</genre>
And in Theme folder you have Default_puzzle.zip and Default_fighter.zip
After verify if a theme without game name exist