New library for PWM playback from SD cards: SimpleSDAudio

Hi, want to add something:

Please also beware of one common made mistake:

If you want to use the 16-Bit feature of the library, you have to set the correct configuration flags: If you want 1 channel mono output but with 16-Bit you have to choose SSDA_MODE_STEREO and not SSDA_MODE_MONO to enable that "magic additional pin that makes audio better".