Updated all PNGs to avoid `libpng warning iCCP incorrect sRGB profile`
Added option to toggle verbose mode on the configuration file
Made `SFX` only emit a Warning when not able to play
Removed warnings about unused variables
Removed "initialized after" warning
Removed warning on "initialized with itself"
Added a global cache for `SDL_Surfaces`, thus avoiding to load the same file twice
Made the sound effects not overlap each other