Tone-deaf

- Fixed up some slicing shortcuts to add overloading
- Inline string parsing (see wiki)
- Palindromizing + checking palindromes
- Fix stack printing
- Add set casting

No new chords have been added, this mostly changes the structure of the interpreter to something easier to navigate.

5 D chords have been added, and now any non-function tokens encountered will be casted to a number if possible and pushed to the stack.

- Removed the useless `message.py` file.
- Fixed the readme that gave proper usage instructions

Since I got around to working on this again, I added a REPL environment and made it a proper package for easy installation.