Complete revision of "main.lua"

HUGE update and advancement to the app!
Because of github, though, I can't change the name to "music.lua", which it is what it ultimately should be called.

Changes:
- New functions to create exclusive "Music" folder for app.
- Songs no longer have to be written into the code! The program will find them on it's own from the Music folder. However, this unfortunately means that you have to move all your songs to the Music folder to listen to them.
- Song names are now displayed!
- Parent functions have been added for easier calling.
- Shortened some function names and revised code.

NOTES:
*This file is no longer syntactically a main.lua, and therefore must be "required" in a main.lua when use is wanted.
*There are still some limitations to the app (memory size, playlist functionality are being worked towards).
*This app can be slow, so you may want to decide if it is useless for power optimization; it can actually hinder your situation.
*Make sure to inspect the new code for any changes or discrepancies.