Super Mario Paint v1.0.0
All major functionality has been implemented and tested to the best of my abilities at the moment. Includes stability fixes, human-readable files, and is fully compatible with any song directories for arranger files, etc.
To load an arrangement, you will need to have all of the song files in the same directory, but it no longer needs to be inside the "Prefs" folder. Can load both MPC and SMP files.
Songs can be saved anywhere, but it's recommended that you make your own "songs" folder...
File-skipping problem appears to be solved.