Completely reworked the Turing Machine

- Removed questionable stack support

- Turing Programs are now objects with their own tapes and settings
- Added inversion program

- Improved core machine's test program
- Fixed error messages having the 'u' prefix for values

- Moved some interface specific code from main.py to gui.py
- Reworked the interface to fit the new Turing Program format
- Added buttons for generating tape values